Focus on California 8th Grade Physical Science Textbook Chapter 4 Elements and the Periodic Table

Elements and the Periodic Table . Standards I Eath the more than OD ments nutter has and a re All of matter are composed of one or more ol the elements As a ham lor under standing this concept Students know the structure 01 the atom and know it Is composed of . and electrons The the table it based on the properties ol lhe elements and reflects the atoms . As I basis for this ( Students how ru regions to menu . And Students know each element has number or melons in the law ( the number ) and math ul the hat . I ( number ol neutrons in the students know ran be by then properties . their , dew my , hardness . and thermal and as is made by meaningful and . As I basis lor understanding and the content In the other three strands . students mould develop their arm question and perform inns . Students will . warrant and on a Int like the In tho bazaar , hy IN

Elements and the Periodic Table How is the periodic table organized ?

Check What You Know Imagine you have a piece of aluminum foil , and you cut it in half . If each of these pieces is cut in half a second , third , and fourth time , the pieces become smaller but are still aluminum . How small must a piece be so that at the next cut it will no longer be aluminum ?

Channel 0119 The images shown here represent some of the key in this chapter . You an use this ( skill to help you understand the meaning of some key terms in this chapter . Greek word Origins Many science words come to English from Greek . For example , the word autograph comes from the Greek word auto meaning self and graph meaning mitten . Therefore , an autograph is one name written in one own handwriting . auto graph autograph self written written in one own handwriting Learn these Greek origins to help you remember the key . Greek Origin Meaning Key Words First letter of the Greek alphabet Alpha particle atomic mass i i '

Chapter Vocabulary Section atom neutron nude number prawn Isotope mug , my mass number Section mew 13 ! atomic mass group periodic table chemical symbol Section nag um metal malleable alkali metal thermal ' accelerator Section nonmetal mert gas semimetal molecule , halogen Section I beta dmy gamma radiation alpha particle Build Vocabulary On line Visit Web ( ode 121

Howe , Read Science ending Skill . Preview Before you read the meme text , to take the ( to preview the visuals are photographs , graphs , tables , diagrams . and contain that helps you understand the ( Follow these steps to preview . Read the tulle I Read the labels and . Ask yourself about the to give yourself a purpose for . I ' the table In Figure 14 of , Use a graphic to ask questions about the tame . Figure 14 Periodic Table of the Elements . Why are most of the squares in the table timed blue ! A . Why do the for some elements in red ?

rows of rhe pole ?

A . Apply It ! Copy the graphic Into your notebook . Answer the as you learn more about the table . the lor and , and ( graphic . 11 Survey Properties of Metals Chemists have system for organizing the elements . There are more than 100 elements , and as you will learn in this chapter , about 80 of them are as metals In this ) you will examine more closely the physical and properties of metals . Your Goal To survey the properties of several samples of metallic elements To complete the investigation , you must interpret what the periodic table tells you about your samples and experiments that will allow you to test at least three properties of your metals compare and contrast the properties 01 your sample metals follow the safety guidelines in Appendix A Plan It ! Study the ( table to determine elements are metals . Brainstorm with your classmates about the properties of metals . What properties allow you to recognize a metal How do you think metals from Your teacher will assign samples of metals to your group . You will be observing their properties in this investigation

Introduction to Atoms Up I Students know the what the Box ture of the atom and know it is composed of protons . neutrons , and electrons ! Students know each element has a number of protons in the ( atomic number ) and eath isotope of the element has a diflerent but number of neutrons in the . Your teacher will give you a sealed box that contains an object . Without opening the box . move the box around to find out as much as you can about the object . Make a list of your observations about the . For example , does the object slide or roll ?

is it heavy or light ?

Is it soft or hard ?

Is the object round or flat ?

Think about familiar ( that could give you clues about what inside the box Think it Over Inferring Make a sket ( showing what you think the object looks like . Tell how you interred the properties of the from observations . How did ( theory develop and What is the modern model of the atom ?

Key Terms ' at the painting and you sci pimple an in the park . Now look at the . i . mow . you that the used til . mug , mall spots to ( route ul and the park , neutron . you that it rich painting can be i i number ' lots at small spots ?

Matter is like , Inn . The properties isotope of matter that you can ' from the properties of ( you can not . you ill ' lint than make up all matter are . mass number FIGURE Sunday Afternoon on the Island of La Grande latte This painting by artist Georges , which is made from tiny dots of paint gives you a simple model for thinking about how matter is made of atoms .

Development of Atomic Theory If you could look into an atom . what might you see ?

Figuring out what atoms are made of hasnt been easy . Because atoms are so small , studying them is a hit like trying to solve the mystery of the sealed box in the Standards activity , Ideas about the shape structure of have changed many times . The first people to think about the nature of matter were the ancient Greeks . Around the year 450 . Greek named proposed the idea that matter is formed pieces that could not be cut into smaller parts . He used the word aromas . which means uncuttable . for these smallest possible pieces . in modern terms atom is the est particle ofan element . The ancient Greeks did not prove the existence of atoms because they did not do experiments . In science . ideas are iust ide unless they can be tested . The idea of atoms began to develop again in the 16005 , This time , however . people did do experiments . As it result , theory began to take shape . Atomic theory grew as I series of models that developed from experimental evidence . As more evidence was collected . the theory and models were revised . Dalton Atomic Theory Using evidence from many . Dalton . an English chemist . inferred that had certain characteristics . He began to propose an atomic my and model for atoms . The main ideas of ) alton theory are in Figure . With only at few changes . alton atomic theory is still accepted today . What is the modern definition of an atom ?

of Dalton All elements or composed of atom . All atoms of the aims element are alike and hava the nine muss . Atoms of clement are different Ind have mason . An atom of one ailment can not In changed into In scant of . Atoms can not be crusted or destroyed in my chemical . only . I Every compound is composed of atoms . combined In . Web ( ode mi For More an atomic Visit ! Dalton Model Dalton thought that atoms were like smooth . hard balls that could not be broken Into smaller pieces . us

Model Through a series of around ! Model the start of the twentieth century , scientists discovered that suggested that atoms had negatively charged electrons embedded in a positive sphere . atoms are made of even smaller parts . In another English scientist . I . found that atoms contain negatively charged particles . Yet , scientists knew that atoms themselves had no electrical charge . So . reasoned . atoms must also contain some sort of positive charge . proposed a model like the one in Figure . He described an atom that consisted of negative charges scattered throughout a bull like raisins or berries in a . The negatively charged particles later became known as electrons . when were the electrons located in Thornton I model of an atom ) Rutherford Model In I ) one of students . Ernest Rutherford . evidence that countered model . In an experiment in Figure . research team aimed a beam of positively charged particles at a thin sheet of gold foil . They predicted that , if model were correct . the charged particles would pass right through the foil in a straight line . The gold atoms would not have enough positive charge in any one region to strongly repel the charged particles . noun Gold Foil Experiment Rutherford was surprised that a law Mo , pas , particles were deflected strongly . This , led him to propose an atomic model ! no Gammon with a positively charged nucleus . A few particles are deflected strongly . loll Gold atoms Positive Source of positively charged particles Particle beam Nude Deflected particles 126

Rutherford team observed that most of the particles passed through the foil undisturbed . as expected . But , to their surprise , it few particles were deflected strongly . Since like charges repel each other . Rutherford inferred that an atom positive charge must be clustered in a tiny region in its center . called the ( us ) The plural of nucleus is nuclei . Any particle that was deflected strongly had been repelled by a gold atom nucleus . Scientists knew from other experiments that electrons had almost no mass . Therefore . they reasoned that nearly all of an moss must also be located in the tiny . positively charged nucleus . In Rutherford atomic model . the atom was mostly empty space with electrons moving around the nucleus in that space . Later research suggested that the nucleus was made of one or more positively charged particles . Rutherford called the positively charged particles in an nucleus protons . Bohr Model In . Niels Danish scientist . revised the atomic model . Bohr showed that electrons could have only amounts of energy . leading them to move in certain orbits . The orbits in Bohr model resemble planets orbiting the sun or the layers of an onion . as shown in Figure . Cloud Modal In the . the atomic model changed again . Scientists determined that electrons do not orbit the nucleus like planets . Instead . electrons can be anywhere in a region around the nucleus . The is a visual model . It symbolizes where electrons are likely to be found . An movement is related to its energy level . or the amount of energy it has . Electrons of energy levels are likely to be found in different places . The energy of each electron keeps it in motion around the positive nucleus to which it is attracted . Bohr Model Niels Bohr suggested that electrons move in specific orbit around the nucleus of an atom . FIGURE Model to model . an atom was mostly empty space . Making Models How in fruit with a pit at its center a simple model for Rutherford idea ?

Mun Later Atomic Models Through the first part of the twentieth century , atomic models continued to change . Cloud Model to the cloud model , electrons move rapidly in every direction around the nucleus . Onward 117 Modern Model of an Atom This model of a carbon atom consists of positively charged protons and neutral neutrons in a nucleus that is surrounded by a cloud of negatively charged electrons . Relating Cause and Effect What effect do the neutrons in the nucleus have an the atom electric charge ?

Explain . Activity How Far Away ?

On a piece of paper , a small circle no bigger than a dime . The circle represents the nucleus of an atom . Measure the diameter of the circle in centimeters . Now predict where the outer edge of this model atom would be . For example , would the outer edge be within the edges of the paper ?

Vour desk ?

The classroom ?

The school building ?

Calculating The diameter of an actual atom can be times that at its nucleus . Calculate the diameter of your model atom . How close was your prediction in Step to your calculation ?

Hint To understand the scale of your answer , change the units of measurement from centimeters to meters ) III ( loud at electrons Nucleus The Modern Atomic Model in , English scientist James Chadwick discovered another particle in the nucleus of atoms . This new particle . called a neutron . was hard to detect because it has no electric charge . A has nearly the same mass as a proton . Chadwick discovery led to an adjustment in the atomic model . This model . pictured in Figure has not changed much since the 19305 . The modern atomic model describes the atom an mostly empty space . At the center of the atom is a tiny . massive nucleus containing protons and neutrons . Surrounding the nucleus is cloudlike region of moving electrons . New research continues to provide data that support this model . These data also many of the earlier made by scientists who helped advance atomic theory . dame closely at Figure . Protons are shown in the diagram by a plus sign ) and electrons are shown by the symbol . lfyou count the number of protons . you see there are same as the number of electrons . in an atom . the number of protons equals the number of electrons . As a result . the positive charge from the protons equals the negative charge from the electrons . The charges balance . making the atom neutral . In contrast , the number of neutrons in an atom does not have to equal the number of protons . Neutrons affect the charge of an atom because they have no charge . Realm Where are the electrons located in the modern model of an atom !

Particles in an Atom Symbol Charge murmur Model Proton I Neutron I Electron Comparing Particle Masses Although electrons may protons , they ca compare when it comes to It takes almost electrons to equal the mass of just one proton . A proton and a neutron are about equal in mass . Together , the protons and neutrons make up nearly all the mass ofan atom . compares the charges and masses of the three atomic particles . are too small to be described easily by ty units of , such as grams or kilograms . scientists use units known as atomic mass units ( amul . A ton or a neutron has a mass equal to about one amu . Scale and Size of Atoms Looking back at the modern atomic model ( Figure ) you may see that most of an atom volume is the space in which the electrons move . In contrast . the nucleus seems tiny . But no image can be drawn in a book that would show how small the nucleus really is compared to an entire atom . To picture the scale of an atom . imagine that the nucleus were the size of an eraser on a pencil . If you put this nucleus on the pitcher mound of a baseball stadium . the electrons could be as far away as the top row of seats ! Atoms are small . The tiniest visible speck may contain ( million billion atoms . Because they are so small , atoms are hard to study . Today powerful microscopes can give 11 glimpse of atoms . as shown in Figure . But they do not show the structure of atoms . Models . such as those shown in this book . are helpful in learning more about atoms . Atomic Number Every atom of a given element has the same number of protons . For example . the nucleus of every carbon atom has protons . Every oxygen atom has it protons , and every iron atom has 26 protons . The number of protons in the nucleus of an atom is the atomic number of that atom element . The of an element is based on its atomic number . Atoms with different atomic numbers are atoms of elements . Carbon atomic number is . Oxygen has an atomic number of iron has an atomic number of 26 . Haunt An atom is composed at positively charged protons . neutral neutron and negatively charged ( Protons and neutrons are about equal in mass . An electron has about the mass of a proton or neutron . Imaging Atom This Image was made by a scanning tunneling microscope . It shows a zigzag chain at cesium atoms ( red ) on a background of gallium and arsenic atoms ( blue ) The colors were added to the image . 129

Neutrons to Isotopes Atoms oi all isotopes of carbon contain protons and electrons . but they differ in their number of neutrons . is the most common isotope . Interpreting Diagrams Which isotope of carbon bar the largest mass number ?

Section Vocabulary Skill Greek Word Origins Use what you know about the Greek word aromas to explain the meaning mom . Reviewing Key Concepts with ?

MINT model ?

i HINT . Reviewing What are the three main particles in the model ol an atom ?

Assessment . Reviewing Why did atomic theory change . Describing Describe Bohr model of the atom . What specific information did Bohr contribute to scientists understanding of the atom ?

Comparing and Contrasting How is the modem atomic model different from Bohr Neutrons Neutrons Isotopes and Mass Number Although the number of tons is for a particular element , the same is not true for the number of neutrons in the nucleus . Atoms of the same that have numbers of neutrons are called isotopes ( suh ) Three carbon isotopes are illustrated in Figure . carbon atom has protons and electrons . But the number of is . or An isotope is by its mean number , which is the sum of the protons and neutrons in the nucleus of an atom . The most common isotope ol carbon has at number of 12 ( protons neutrons . and may be written as . Two other isotopes and . Despite their different mass . all three carbon isotopes react the same way chemically . also has three isotopes . All hydrogen atoms one proton in the nucleus . The most common isotope is proton ) others are ( ton neutron ) and ( proton neutrons ) is called deuterium . is called tritium . HA Reading . Explaining What is atomic number ?

How is it used to distinguish one element from another ?

Applying Concepts The atomic number of nitrogen is . How many . neutrons , and ' make up in atom of IS ?

Modeling Atoms Build a model of an atom using materials sud as beads , cotton , and clay . Show the model to your family , and explain what makes atoms of different elements different lrom one another .

Standards Fo CAL Students know how to identify regions corresponding to metals . and inert gases How did the pattern that led to the periodic table ?

How are the elements organized in the modern periodic table ! Key Terms mass periodic table I period group I chemical symbol Organizing the Elements . Standards which Is Easier ?

Make sets of 10 paper squares , using a different color for each set . Number the squares in each set from through 10 . Place all at the squares on a flat , numbered side up . Do arrange them in order . Ask your partner to think of a way of arranging the squares that makes it easy to find a square of a particular color and number Have your partner describe to you how the squares should be organized . Working together , arrange the squares according to the organization scheme devised by your partner . Trade places with your partner and repeat Steps through . Try to think of a different organization scheme than the one devised by your . Think it Over Drawing Conclusions Compare the different ways that you and your classmates organized the squares . Were some schemes more organized than others ?

Explain . You up . out ul bud . and start to got dressed for school . Then you ask yoursell ' i question is their school today ?

To tind out . you check the calendar . no school today ifs Saturday . The the days of the month in periods called and groups days Lil the week . This arrangement follows rep pattern that lI ( it easy to keep track of which day it is . The chemical elements can also be into like it calendar . The name of the clu ir is periodic table . A calendar organizes the days of the week Into a useful . repeating pattern . Channel 9131

how 11 Metals That Tarnish A copper weather vane and a silver spoon both tarnish from contact with air . Mauls That Rout With Lithium and bath read with water . Interpreting Photographs metal react more vigorously with water ?

132 Periodic Table By , a total of 63 had been discovered . A few gases . Two liquids . Most solid metals . Some reacted explosively . Others ' more . Scientists wondered if the properties of elements followed pattern . A Russian cit , Dmitri ( men duh HY . of that to all the ! Patterns of Properties knew that have similar and itl UpL ' For ' both and chlorine arr games that irritate the lungs and form similar compounds . Silver copper . shown in Figure II . are both shiny metals that tarnish if exposed to air . thought similarities clues to hidden . To lind that pattern . vault melting point ( density . aural on curds . also included the ' nia . atomic mass is the average mass of all the isotope of an element tried arranging the cards in noticed that a pattern of properties appeared when he arranged the elements in order of increasing atomic mass . For . when the 63 known elements were arranged in this order . lithium Li in . sodium ( Na ) ante in ninth . and ( came in . Each of with in same way . So . lined up the cards for these elements to form their own group . He did same with other similar . Group by group , constructed the tint periodic table . A periodic table is an of ment showing the pattern of their properties . The word periodic in regular , repeated pattern ) What do silver and copper share !

Predicting New Element found that ing the known elements strictly by increasing atomic mass did not always group similar elements together . So . he moved a few of his element cards into groups where the elements did have similar properties . After arranging all 63 elements , three blank spaces were left . predicted that the blank spaces would be by elements that had not yet been discovered . He even predicted the properties of those new elements . in , published his periodic table . It looked something the one shown in Figure 13 . Within 16 years , chemists discovered the three missing . gallium , and germanium . Their properties are clone to those that had predicted . The Modern Periodic Table The periodic table changed as scientists discovered new ments and teamed more about atomic structure . The modern periodic table contains more than too elements . It is also differently from Mend table . in the modem odic table , the elements are arranged in order of increasing atomic number . Recall that the number of an element equals the number of protons in an atom of that element . The modern periodic table appears on the next two pages . location on the periodic table . This predictability is the rea son that the periodic table is so useful to chemists . mun little when his ! periodic table . he question marks in some planet Based on the properties and atomic mates of surrounding element he that new elements with would be discovered .

BOWEN Table of the Elements . element can be ac ark predicted by Its III the table . or I . aim Id Cad ) Symbol one or symbols must elements . some table also the names of the elements . The and the are placed off the table to save spece and to make the rest of the table read . Follow the blue shading to see how they fit in the table . 1340

Ins Atomic mass is the mass of an element atoms . Atomic masses in are those of the mom stable . Annual The atomic is the number of protons in an atom . Many periodic tables Include a zigzag line that separates the metals from the . Name um ( Atomic mum in on that ol the man mun Am Es

Classifying Choose any ten elements and assign them letters from A to 14 On an Index card for each element . write the letter for the element and list sortie at its properties . You may list properties that you learn about in this chapter or properties presented in another reference source . cards with a classmate . Can you identify each element ?

Can you identify elements that have similar properties ?

which properties are most helpful in identifying elements ?

15 An Expanded Periodic Table If the and were placed within the body of the periodic table . they would increase the number of groups to 32 . Look at Figure on the previous two pages . starting at the upper left with hydrogen . Notice that the atomic numbers increase from left to right . You may also notice that the table is . Each region corresponds to a different class of , and inert gases . Periods The periodic table is organized in rows called periods . A period contains at series of different elements . From left to right . the properties of the elements change in a pattern . Metals are shown on the left of the table . with the most reactive metals on the far left . are located on the right . with the most reactive next to the inert gases on the far right . are found between the metals and als . This pattern is repeated in each period . Typically , the atoms of elements increase in mass from left to right . and elements in lower rows are more massive than those in the upper rows . The periodic table contains seven periods . Period I has two elements . Periods and each have elements . Periods and each have 18 elements . Period has 32 elements . Notice that some of the elements in Periods and are placed off the table to save space . These elements are the and Groups The vertical columns of the periodic table are called groups . A known as a of elements with similar characteristics For example . the elements in Group I react violently with water . while the elements in Group react with water slowly or not at all . Group 17 elements react violently with Group I demerits . but Group 18 elements rarely react at all . The and the do not belong in the groups labeled in Figure . Figure IS different form of the periodic table . It includes the and where they would lit . according to their atomic numbers Because this form of the table is so wide , it is to lit in a book unless you show only the elements symbols . landing How many periods does the periodic table contain ?

Reading The Data In the periodic table . there is one square Raul 16 for each element . In this book , each square in the periodic 00 table lists four pieces of information an element a atomic i ' 26 number , chemical symbol , name . and atomic mass . am . hay . be , Iron ( Fe ) is the element located in Group . Period of the is a leafy vegetable rich In iron . periodic table . You can see the square for iron reproduced in . HOW ' Figure . The first piece of information in the square is the ' number 26 , the atomic number of iron . An atomic number of 26 tells you that every iron atom has 26 protons in its nucleus . lust below the atomic number are the letters the symbol for iron . A chemical symbol is a representation ofan clement usually ing of one or two letters . Often , a chemical bol is an abbreviation of the element English name . For example . the symbol for zinc is . and the symbol for calcium is Ca . Other symbols are abbreviations of Latin names . For example . the Latin name of iron . so its symbol is Fe . Still other elements have names derived from the last names of scientists . For example . Curium ( is named after the French scientists Pierre and Marie Curie . The last number in the square is the atomic mam . For iron , this value is atom . The atomic mass is an average because most elements consist of a mixture of isotopes . For example , iron is a mixture of four isotopes . About 92 percent of iron atoms are having 30 neutrons ) The rest are a mixture of , and . The atomic mat of iron is determined from the combined percentages of all its isotopes . target Reading Skill Preview Visuals Review II . Comparing and Contrasting your graphic organizer for Figure . How did you differences between periodic answer your questions ?

table and the modern periodic table . Interpreting tables What element has Reviewing Concepts 47 protons in its nucleus ?

EE . I . Reviewing In what order did ?

i a . In Silence discover when be arranged the elements ?

Interpreting Tables What elements did a i um group with lithium in his 59 53 ' to chemists In 1869 . Listing What information is listed in an 59 . clement square in the periodic table ?

Students know how to identity regions corresponding to metals . and inert gases . Students know can by their properties , including their melting ture , density , hardness . and thermal and electrical conductivity , What are the physical properties of metals ?

How does the reactivity of metals change across the table ?

How are synthetic elements ?

Key Terms metal I malleable ' ductile I thermal conductivity ele ( reactivity ( alkali metal alkaline earth metal I transition metal 13 ! Metals Standards Why Use Aluminum ?

Examine several objects made from aluminum , including a can , a disposable pie plate , aluminum foil , wrapping paper , and aluminum wire . Compare the shape . thickness , and general appearance of the objects . Observe what happens if you try to bend and unbend each obiect . For what purpose is each object used ?

think It Over Inferring Use your observations to list as many properties at aluminum as you can . Based on your list of properties , infer why aluminum was used to make eath obiect . Explain your answer . It hard to imagine life without . The cars you iii are of , which is iron . arc in . A is coated with copper . Copper carry electric current to lamps . Properties of Metals can be by . including inciting . il . and thermal and conductivity . Metals arc that are good current and him . They also to be shiny and hend copper wire . for instance . The of in the periodic table arr metals . Physical Properties The physical properties of metals include luster . ductility , and conductivity . A malleable MAX uh bul ) is ) that can be rolled into or shapes . A ductile is uni that bi pulled out , or . into zi long wire . Copper is both and . It be into thin sheets or drawn into wires .

Thermal conductivity is this ability of an object to heat The ability of an to transfer current is electrical conductivity . Most arc good and electrical conductors . In addition . some metals are magnetic . For . iron ( cobalt ( Co ) and ( Nil arc attract to and can maid into . Most metals are also solids at room . um ( liquid at room . Chemical Properties The ease and speed with which a substance reacts with other substance is called its reactivity . Metals usually react by losing electrons to atoms . metals are very re ' For . sodium ( Nit ) reacts strongly when to air or water . To prevent it from ing . must he under oil in , By comparison . gold Au and platinum are very . The of other metals fall between those of sodium and gold . Iran . for example . reacts slowly with in the air . forming iron . or rust . is not by paint or plated with another , it will slowly tum to rust . gradual away of a metal due to a chemical reaction is called corrosion . What an three physical properties of metals ?

FIGURE Properties of Metals Metals have certain and chemical properties Classifying Categorize euh at the properties of metals that are shown as either physical or chemical , Some metals are Gold Can be attracted to magnets . into ( This iron chain is coated with rust after being exposed to alr .

18 Alkali Metals Potassium is an alkali metal . Making Generalizations What do other elements share with potassium Potassium is highly reactive with air . so it is stored in oil Bananas are a good source of potassium in a healthful diet . A The reactions of some containing potassium help get fireworks oft the ground . Metals in the Periodic Table The in group , have . and these Family change gradually as yuu ( the table . The reactivity of metals tends to decrease as you move from left to right across the periodic table . Alkali Metals The metals in ( I , lithium ' are ( the alkali Alkali . in Figure . react with other elements hy losing . metals are so reactive that they are never as in nature . Instead . they are only in . In the laboratory . scientists have been able isolate alkali metals from their . As pure . some of the ( are shiny and so sun that you can cut them with a plastic . he mu important metal are and , slum . Sodium ale in large in . and salt beds . Your oi sodium and . Another alkali metal , lithium . is used in batteries and some medicines . what are the alkali metals touted in the I . table ?

Alkaline Earth Metals Group of the periodic table contains the alkaline earth metals . Each is fairly hard , and good conductor of electricity . Alkaline earth react by losing electrons . These elements are not as reactive as the metals in Group but they are more than most other . Like the Group metals . the Group metals are never found in . and calcium arc the most common earth metals . Mixing and ii small amount of a strong but lightweight used in ladders . wheel rims . and airplanes . Calcium compounds are an essential part of teeth and bones . Calcium also helps work properly . Comparing ( atomic number 12 and sodium ( atomic number 11 ) shows how slight change in atomic structure can result in properties . is ! hard metal that melts in ( Sodium is a soft metal that melts at . 19 Alkaline Earth Metals Calcium one of the Group elements . without Calcium . muscles and bones can not grow and function . Math Algebra and Functions Melting Points of Alkali Metals Analyzing Data I . I Melting Points in a Group of Elements The properties of elements within a single group in the periodic table often vary in a certain pattern . The following graph shows the melting points of Group elements ( alkali metals ) from lithium to francium . Reading Graphs As you look at Group from lithium to francium , describe how the melting points at the alkali metals change . Predicting If element number 119 were sized . it would fall below in Group of the periodic table . Predict the approximate melting point at new element . Interpreting Data which of the alkali metals are liquids at ?

141 ' Transition Metals The elements in Groups through 12 are called the transition metals . The transition metals include most of the familiar metals . such as iron , copper . nickel . silver , and gold . Most of the transition metals are hard and shiny . All of the transition metals are good conductors of electric rent . Many of these metals form colorful compounds . The transition metals are less reactive than the metals in Groups I and . When iron reacts with oxygen . forming rust , it sometimes takes many years to react completely . The lack of reactivity of gold is the reason ancient gold coins and jewelry are as beautiful today as they were thousands of years ago . Still . most transition metals are never found uncombined in nature . Some transition metals are important to your . For example . iron forms the core of a large molecule called globin . which oxygen in your ' Metals In Mixed Groups Only some of the elements in Groups 13 through 15 of the periodic table are metals . These metals are never found uncombined in nature . The most iar of these metals are aluminum . tin . and lead . Aluminum is the lightweight metal used in beverage cans and airplane ies . A thin coating of tin protects steel from corrosion in some sums of food . head was once used in paints and water pipes . But lead is poisonous , so it is no longer used for these purposes . Now . its most common uses are in automobile batteries and . weights for balancing ' Two rows of elements are placed below the main part of the periodic table . This the table more compact . In the top row are the ( LAN ) are sometimes mixed with more common metals to make alloys . An alloy is a mixture of it metal with at least one other element . usually another metal . are usually found together in nature . always combined with other elements . Two Group ( and yttrium ( also show properties similar to the . So . scientists group scandium . yttrium . and the together as the rare earth elements . Some rare earth elements can be used to produce very strong magnets .

20 Transition Metals Compounds made with transition metals can be very colorful . Several compounds are used to make paints . Flaunt 11 Metals in Groups ! and 15 Lead ( an be used in the borders around the glass sections in stained glass objects . Tin can be fashioned into artistic objects , sum as picture frames . Neodymium is used in manufacturing the tiny speakers inside stereo headphones annual 0143

! 23 Curium . one of the elements , is used as a source of particles that heat and provide power for certain scientific equipment aboard the Mars Exploration Rover . Posing Questions Based on this information , write a question about curium . Online ( crisp INKS . For Links on metals ( Web Code The elements below the are called ( AK tuh . Of the , only actinium ( Ac ) thorium ( Th ) protactinium ( Pa ) and uranium ( occur naturally on Earth . Uranium is used to produce energy in nuclear power plants . All of the elements after uranium were created in laboratories . The nuclei of these ments are very unstable . meaning that they break apart very quickly into smaller nuclei . In fact . many of these elements are so unstable that they last only a fraction of a second after they are made . Synthetic Elements Elements with atomic numbers higher than 92 are sometimes called synthetic elements . These elements are not found rally on Earth . instead , scientists make . or , them . Scientists malt synthetic elements by forcing nuclear particles to crash into one another . For example . plutonium is made by bombarding nuclei of with neutrons in a nuclear reactor . is made by bombarding nuclei with neutrons . To make even heavier elements ( with atomic numbers above 95 , scientists use powerful machines called particle accelerators . Particle accelerators move atomic faster and faster until they have reached very high speeds . if these nuclei crash into the nuclei of other with enough energy , the particles can sometimes combine into a single nucleus . Curium ( was the tirst synthetic to be made by vol nuclei . In scientists in Chicago synthesized curium by colliding helium nuclei with plutonium nuclei . In general . the difficulty of new increases with atomic number . 50 , new have been only as more powerful particle accelerators have been built . For exam ple . German scientists synthesized element I 12 in 1995 by accelerating nuclei and crashing them into lead . Element . like other elements with symbols . has been given a temporary name and symbol . the future , around the world will agree on names and symbols for these elements . Which elements are described as synthetic ?

elements and why ! ( is produced in nuclear . It is widely in smoke detectors . The heaviest synthetic FIGURE 24 elements are synthesized in . Synthetic elements are not lound naturally on Earth section Assessment Target Reading Skill Preview Visuals , Inferring ofthe periodic table ! your lor 17 . Huw did mutants the . yuu your qu ?

Which is thu ?

Key . new ' are ) um ?

Applying come and ' ii . Classifying Um an the can . Inferring . inc Ill plastic in on Activity metal cooking . mu What ul in he Vi YOU Om ?

table mutants the must reactive label ' dietary supplements . medicines . and by coma , um um . Also look for examples is ! how metals are table is the plat lu my In your home . such as Ir cookware and metal that could he used to mat ' fY ' to ?

make them useful ' my life . 145 Consumer Lab Copper or Carbon ?

That Is the Question Problem Materials scientists work to find the best als for different products . In this lab . you will look for an answer to the following problem How do the properties of copper and graphite determine their uses ?

You will compare the properties oi a copper wire and a pencil lead . Pencil lead is made mostly of graphite , a form of the nonmetal element carbon . Skills Focus observing . classifying , controlling variables , drawing conclusions Materials dry cell battery beaker stopwatch flashlight bulb and socket lengths of insulated wire thin copper wire with no insulation , about long graphite samples ( lead from a mechanical pencil ) each about long hot plate water Procedure . Fill a beaker about full with water . Heat it slowly on a hot plate . Let the water continue to heat as you complete Part I and Part of the investigation . Physical Properties . Compare the shininess and color of your copper and graphite samples . Record your observations . Bend the copper wire as far as possible . Next . bend one of the graphite samples as far as possible . Record the results of each test . Electrical Conductivity . Place a bulb into a lamp socket . Use a piece of insulated wire to connect one pole of a dry cell battery to the socket , as shown in the photo below . Attach the end ol second piece of insulated wire to the other pole of the dry cell battery . Leave the other end of this wire tree . Attach the end of a third piece of insulated wire to the other pole of the lamp socket . Leave the other end of this wire free . Touch the free ends of the Insulated wire to the ends of the copper wire . Record your observations of the bulb . Repeat Step using a graphite sample instead of the copper wire .

Thermal Conductivity . Turn off the hot plate . 10 . Hold one end of a graphite sample between the fingertips of one hand . Hold one end of the copper wire between the fingertips ol the other hand . Be careful not to touch the beaker . 11 . Dip both the graphite and copper wire into the hot water at the same time . Allow only about i an of each piece to reach under the water surface . From your fingertips to the water , the lengths of both the graphite sam ple and the copper wire should be mately equal . 12 . how long it takes to feel the heat in the fingertips of each hand . Record your observations . Analyze and conclude . Observing Compare the physical properties of copper and graphite that you observed . Based on the observations you made in this lab , explain why copper is fied as a metal . Controlling Variables parameter was controlled in Step of the procedure ?

why it was important to control this parameter . Drawing Conclusions which of the two materials , graphite or copper , would work better to cover the handle of a trying pan ?

Explain your choice , Communicating Write a paragraph ing why copper is better than graphite for electrical wiring . Include supporting from your observations in this lab . More to Explore Research other uses of copper in the home and in industry . For each use . list the physical ties that make the material a good choice . 147

Standards Focus , a Students know how to identify regions corresponding to metals . and inert gases re students know substances can by , including their melting tempera tum entity , hardness , and thermal and . What are the properties of arid inert gases ?

how are Key Terms I I diatomic molecule I halogen I inert gas I I semiconductor These bears , the grass behind them . and all life on Earth are based on carbon , a nonmetal . MI , Inert Gases , and , Up What Are the Properties of Charcoal ?

Break off a piece of ( har ( and roll it between your fingers . Record your observations . Rub the charcoal on a piece of paper . Describe what happens . Strike the charcoal sharply with the blunt end of a fork Describe what happens . When you are finished with your investigation , return the charcoal to your teacher and wash your hands . Think It Over Classifying Charcoal is a form of the element carbon . would you classify carbon as a metal or a nonmetal ?

Use your observations from this activity to explain your answer . life on Earth depends on certain . For example . the you ) oxygen . is essential to the up all living , make up the ' elements in the periodic . In this you will other ' of , inert gases , and .

are good insulators . Carbon compounds are round A A ( diver an , the insulating tank contains mostly nitrogen and oxygen . which are gases at room temperature . Properties of nonmetal is an that lacks most of the of a . Most are poor conductors of electric current and heat . Solid are dull and brittle . Look at the periodic table again . All of the in light green tinted boxes are . of the are ( on ' Physical Properties Four arc gases at room . The air you breathe is mostly mixture of two . nitrogen ( and oxygen ( Other . such as carbon ( incline ( and sulfur ( are solid at room . Bromine ( Bri is the only that is liquid at room . look at examples of in Figure 23 . In general . the physical properties of arc the opposite of metals . Solid are dull , nut , and brittle . not or ductile . you hit most solid with at . they break or crumble into powder . are also poor conductors of heat and . these copper wires . A Sulfur crumbles into powder . FIGURE 15 Physical Properties of have properties that are the of metals . and Contrasting Contrast the properties of these nonmetal with those of metals . Chapter I 149

26 Reactions of Mammals The table salt on a pretzel is mined from deposits on Earth . the same compound can also be formed from a reaction between the metal sodium and the nonmetal chlorine . 150 Chemical Properties Atoms of ally gain or share electrons when they with other atoms . and metals . electrons move from the metal atom to the metal atoms , as shown by the formation of salt , shown in Figure 26 . Another example is compound made of iron and oxygen ( It reddish . coating you might sec on an old piece of steel or an iron nail . Many can also form compounds with other . The atoms share electrons and become bonded together into molecules . Rating In which portion of the periodic tabla , do you ?

Families With Look again at the periodic table . Notice that in Groups through , there is a mix of and other kinds The Carbon Family Each element in the carbon family has atoms that can gain . lose , or share four electrons when reacting with other . in Group . only carbon is it nonmetal . What carbon especially is its role in the of life . Molecule containing long chains of carbon atoms are found in all living things . Most of the fuels that are burned to yield energy contain carbon . Coal , for example . is mostly the ment carbon . Gasoline is made from crude oil . a mixture . with chains off to St or more carbon atoms in their molecules . 27 carbon Charcoal is one form of carbon . the only nonmetal in Group 14 ,

The Nitrogen Family the nitrogen . mins two . nitrogen and phosphorus . These usually gain or share three electrons when reacting with elements . is 80 percent nitrogen gas . gen occurs in nature as which is diatomic molecule . A diatomic molecule is that consists of two atom . in this form . nitrogen is not very reactive . Although living things need nitrogen . must are In use from the air . kinds of ' I ( am use this nitrogen to compounds . This process is called nitrogen . Plants can then take up these compounds in the by the . also add compounds to the soil in the form of fertilizers . Like all mals . you get the you new rum the loud you eat from plants . from animals that ate plants . Even though nitrogen and appear next In each other an the table , they have very different . bon is in solid up to very high temperatures ( gen is gas until it is cooled below his illustrates how just slight change in structure can result in ! properties . is the other nonmetal in the nitrogen family . is much more reactive than . so rus in nature is always found in compounds . Flaunt ! The Nitrogen Family Nitrogen and phosphorus are grouped in the same family of the periodic table , Group . Making Generalizations How do atoms of both these change when they react ?

Nitrogen is a key ingredient of fertilizers . A Match heads contain a highly reactive phosphorus ( that ignites easily . 151 735 Try This Activity Show Me the Oxygen How can you test for the presence of oxygen ?

Pour about a depth of hydrogen peroxide ( into a test tube . Add a amount of manganese dioxide ) to the test tube . Observe the test tube for about minute . when instructed by . your teacher , set a wooden splint on fire . Blow the splint out after seconds and immediately plunge the glowing splint into the mouth of the test tube . Avoid getting the splint wet . Observing Describe the change II ' I matter that occurred in the test tube . What evidence indicates that oxygen was produced ?

FIGURE 19 The Oxygen Family The oxygen and are the most common elements in Group . Interpreting Tables What is the atomic number Group 16 element ?

The rubber tires ( The Oxygen Family Group the oxygen . contains three . These elements usually gain or share two when reacting with other ( You are using oxygen right now . With ' travels into your lungs . There . it is absorbed into your . which distributes it all over your body . You could not live without steady supply of . Like nitrogen . the gen you is a molecule ( 13 ) In addition . forum ! which is called , Ozone collects in layer in the upper . where it screens from the sun . However , is at pollutant at ground level it its highly . is . it ( ill with almost every other element . It also is the most ment in Earth crust and ' abundant in the ' Thu is is the other nonmetal in oxygen . It you blI ) ilL ' the odor of rotten egg . you are already with the smell of some sulfur compounds . is in the lut ' oi automobile tires . Most sulfur used to sulfuric acid SO , one ofthe most important used in industry . A Some at the oxygen needed by a frog enters through its skin

The Halogen Family Group contains . and . These elements are also known as the halogens , which forming . All but ( arc ( A typically ur sham one it reacts with other . wit All oi the arc , and the web ( elements are dangerous to humans . is so reactive than it reacts with almost every other known substance . liven water and glass will burn in . gas is , but it is used in amounts to kill bacteria in water supplies . Though the halogen . many of the that form are quite . of carbon and nuke up the nonstick coating on . Small of compounds that are to water supplies help prevent tooth . is one of the clement in hall ( the other is sodium ) will of ( calcium . it used to help roads and . Bromine reacts with silver to form silver , which is used in . For Links on Haunt 30 The Halogens The Group 17 elements are very reactive . Atoms of these elements easily compounds by sharing or gaining one electron with atoms of other elements . Bromine is highly reactive . and will burn skin on ( A compounds are found in toothpaste . 9153

FIGURE The Gases makes the Group Moments glass tubes Applying Concepts Why are neon and the other noble so ?

Inert Gases Thu In ( IX arc . nut gusts not usually gain , ur share . The inert gases to . are . Scientists have been able to some gas in . as . All the in ) but only in small . arc so . the gnaw were not nver until the ) have with helium . an ! arc also in glowing lights . Them lights arc ( rven filled with . or inert ' What is another name for the inert gases ?

Hydrogen the of ' with . Maul have unc and one ( tron . also ' Brutus the at wry rum of thy , it run ! grouped . Although up than 90 ul the in ( up only I percent at the man crust . i ' found on Earth as pun . th in il ' 31 Important ! at Hydrogen Water ( of hydrogen and oxygen Without liquid water , Wife on Earth be .

HINT metals and the ( in the ) lie the . arc in the yellow squares in the periodic table . some metals hut also have that are typical of . All arc ( at . They are , hard , and . The most common is silicon . Silicon with to form silicon dioxide Si ( sand , which is mostly , is the . of boron ( and oxygen is added during of to glass . pounds of are also used in mine cleaning materials . The most useful property of the is their varying ability to conduct electric current . The conductivity at at can on temperature . exposure to light , or the of . are of semiconductors , or substances that can conduct ' some conditions but not ) I ( Il ( and ( are ! Il ' materials . arc lo i chips , and ( What is the most common ?

Assessment Vocabulary Skill Greek Word Origins Hun dim the iii the Greek mird you remember the word Reviewing Key Concepts a . Listing What are some tit ?

Making In the when they react with other ?

Comparing and Contrasting the physical and halogens ( with ul ' inert gases ?

Identifying Where in ' an the found ?

Describing What are three uses of ?

Applying Concepts What . Io current and tilt ?

haunt 33 Silicon A silicon computer chip is dwarfed by an am , but the min properties as a make it a part oi modern computers . leading Activity Halogen Hunt identify compounds in your home that contain halogens . Look at labels on foods . cooking ingredients , cleaning materials . medicines . and cosmetics The presence of a halogen is often indicated by the words , chloride , bromide , and iodide or the , and . Show your family these examples and describe properties of the halogens . 155

Alien Periodic Table , Problem Imagine that inhabitants of another planet send a message to Earth that contains information about 30 elements . However , the message different names and symbols for these elements than those used on Earth . Which ele ments on the periodic table do these alien names represent ?

Skills Focus drawing conclusions , classifying , interpreting data , inferring 156 Materials ruler periodic table lrom text for reference Procedure . Copy the blank periodic table on the next page into your notebook . Listed below are data on the chemical and physical properties of the 30 elements . Place the elements in their proper position in the blank periodic table . Alien Elements The Inert gases are ( Bo ) wobble . Wo ) and ( Among these gases , wobble has the greatest atomic mass and the least . Logon is lighter than . The most reactive group of metals are ( By ) chow ( GI ) and ( Of these metals . chow has the lowest atomic mass . is in the same period as wobble . A ) and Iran ( are whose atoms typically gain or share one electron . is in the same period as and wobble . The are ernst ( Hi ) and ( is the semimetal with the greatest atomic mass . Ernst is the with the lowest atomic mass . and are in Group 14 . has more protons than . touches the zigzag line , but it a metal , not a . a . I ! The lightest element of all is called ( The heaviest element in the group of 30 elements is eldorado ( El ) The most chemically active nonmetal is . reacts with to form table salt . The element doggone ( has only protons in its atoms ( is important in the chemistry ol life . it forms compounds made of long chains of atoms . and ( Do ) are metals in the fourth period , bin is less reactive than . goldy ( and are all members of Group 15 . Goldy has fewer electrons than . Up ) oz ( 01 ) and ( Nu ) all gain electrons when they react . is found as a diatomic molecule and has the same properties as a gas found in Earth atmosphere . 02 has a lower atomic number than . The element ( An ) has atoms with a total of 49 electrons low ! I ) and pie ( Pi ) lose two electrons when they react . Zapper is used to make lightweight alloys

! if . 13 15 17 Analyze and conclude I . Drawing Conclusions List the Earth names for the 30 alien elements in order of atomic number . Classifying Were you able to place some ments within the periodic table with just a single clue ?

Explain using examples . Interpreting Data Why did you need two or more clues to place other elements ?

Explain using examples . Inferring Why could you use clues about atomic mass to place elements . even though the table is now based on atomic numbers ?

telescopes In New . paragraph ing which groups of elements are not included Ill the alien periodic table , Explain whether or not you think it is likely that an alien planet would lack these elements . More to Explore Notice that Period is incomplete on the alien periodic table . Create names and symbols for each of the missing elements . Then , compose a series of clues that would allow another student to identify these elements . Make your clues as precise as possible .

Section Integrating Focus 00 I Students know each ale has a number ol pro Ions in the nucleus ( the atomic number ) and each isotope ol the element has number of neutrons in the nucleus How was radioactivity discovered ?

What types of particles and energy can radioactive decay produce ?

In what ways are radioactive isotopes ul ?

Key Terms I radioactive decay I alpha I beta I gamma radiation I FIGURE 34 Trying to Make Gold From Lead This painting from 1570 shows people trying to change lead into gold No such ( reaction was ever . 153 What Happens When an Atom Decays ?

Count the number of protons and neutrons left in your Think Over Drawing What element does your nuclear model now represent ?

How do you know ?

What IS the mass number ol the new model nucleus . is an unstable isotope of the element beryllium . Radioactive Elements Standards Using green beads to represent protons and purple beads to represent neutrons , make a model of a nucleus . Your model should contain protons and neutrons . Its atoms can undergo decay by losing a particle made of two protons and two neutrons . Remove the appropriate number of heads your model to represent this process . model . lind way In turn lead gold ?

than years . many people it was it great . Inn . They tried think . is no ( that one element into another . Even so . do into other elements . or . atoms can heroine atoms at nitrogen . lend never changes into gold . is it possible for to happen ?

Radioactivity that with the ut Ii , and ) ol tin called . Sonic are that is . their nuclei do not hold together well . In process called radioactive decay . of ( and Discovery of Radioactivity In the French scientist Henri discovered the effects of radioactive decay by accident while studying a mineral containing uranium . observed that with to , the mineral gave , that . that was fur i ' ho . when the . put his in ! dark , including it thu ' ta in . Liter . when his desk retrieve , to find an on the plate . Sunlight ' that gives oft . called , the , i In ii , Marie Curie . and her . study . ra was the uranium nuclei . The uranium showed to emit i ( radioactivity . Polonium and Radium Marie was to rind that ) even more than pure uranium . that the of ( highly ' the ( to wink . They two lIlt . which Mario and . 36 Marie Curie Marie Curie , her husband Pierre , and pioneered the study of radioactive elements 35 Radiation Ftom Uranium As with Be ( radiation from the mineral has exposed 159

! 37 Radioactive Decay Radioactive elements give off particles and energy during radioactive decay . Interpreting Diagrams which type or radioactive decay produces a negatively charged particle ?

Alpha Radioactive nucleus Beta protons and neutrons lost Alpha particle Radioactive One less neutron nucleus one more proton Beta particle Radioactive No gain or loss nucleus of particles Gamma rays 1600 Types of Radioactive Decay There are three major forms of radiation produced during the radioactive decay of an unstable nucleus . Radioactive decay can produce alpha particles , beta particles . and gamma rays . The particles and energy produced during radioactive decay arr forms of nuclear radiation . Alpha Decay An particle consists of two protons and two neutrons and is positively charged . It is the same its a helium nucleus . The release of an alpha particle by an atom decreases the atomic ber by and the mass number by . For example . a nucleus ( atomic number 90 ) decays to produce an alpha particle and a nucleus ( atomic number 83 . Beta Decay Some atoms are unstable because they have too many neutrons . During beta decay . a tron the nucleus of an unstable atom changes into a negatively charged beta particle and a proton . A is a electron given off by a nucleus during radioactive decay . The new proton remains inside nucleus . That means that the nucleus now has one less neutron and one more proton . its mass number remains the same but its atomic number increases by . For example , a nucleus decays to produce a beta particle and a nucleus . Gamma Decay Alpha and beta decay are almost always accompanied by gamma radiation . Gamma radiation consists of waves . similar to . Gamma radiation ( also called gamma rays ) has no charge and does not cause a change in either the atomic mass or the atomic number . Effects of Nuclear Radiation Although alpha move very fast . they are stopped by collisions with atoms . In Figure 38 , you can see that alpha are blocked by a sheet of paper . Alpha radiation can cause an injury to human skin that is much like a bad bum .

33 The Penetrating Power of Nuclear Radiation me three types of nuclear radiation were named based on how easily each one could be blocked . Alpha . beta , and gamma are the first three letters of the Greek alphabet . Inferring which type of nuclear radiation is the most penetrating ?

Mon gamma rays are blocked . Beta particles Alpha particles are blocked . Alpha Radioactive pa nigh concrete Bela particles are much faster and more penetrating than alpha particles . They can pass through paper . but they are by an aluminum sheet millimeters thick . Beta can also travel into the human body and damage its cells Gamma rays are the most penetrating type of radiation . You would need a piece of lead several centimeters thick or a concrete wall about a meter thick to stop gamma rays . They can pass right through a human body , delivering intense energy to cells and causing severe damage . How can radiation affect the body ?

Predicting Look at the table at radioactive isotopes below . Isotope Alpha Using Radioactive Isotopes . we Radioactive isotopes have many uses in science and industry . In some cases . the energy released by radioactive isotopes is ad 22 itself useful . Nuclear power plants . for example , harness this why , help of , energy to generate electricity . in other cases , radiation is table , predict the element because it can be easily detected . Uses of radioactive that forms in each use . isotopes include the steps of chemical reactions Ind ' industrial processes , and diagnosing and treating disease . capture

Go For Radioactive tracers activity Visit Web Code Solution with radioactive is added to the soil . Gamma radiation I is absorbed by the roots of the plant and mules up the am . FIGURE 39 Radioactive Tracers added to soil is absorbed through the roots . The tracer can be detected in any plant structures in which phosphorus is used . Uses in Science and Industry Like a lighthouse flashing in the night , a radioactive isotope signals where it is by ting radiation that can be detected . are radioactive that can be followed through the steps of a chemical reaction or an industrial process . Tracers behave chemically the same way as forms of an element . For exam ple , phosphorus is used by plants in small amounts for healthy growth . As shown in Figure a plant will absorb radioactive added to the soil just as it does the tive . Radiation will be present in any part of the plant that contains the isotope . in this way . biologists can learn where and how plants use phosphorus . In industry , tracers are used to find weak spots in metal pipes , especially oil pipelines . When added to a liquid . tracers can mily be detected if they out of the pipes . Gamma rays can pass through metal and be detected on a photographic film . By looking at the images . structural engineers can detect small cracks in the metal of bridges and building frames . Without these images , a problem might not be ered until a disaster occurs . what is a tracer !

Uses in Medicine use ' to detect to treat mine diseases . the hotly and ( is . hint that , Ui this ' or organ . with 99 air in ' i , and . In i ' in . are used In unhealthy cells . gum IU with ' i ' in thy ' gland . lint ' il ) 13 ) in ' this isotope cells in the on . bird ) iii in kinds ( min the built with ' rays . ill or this . is ' it muses thingy kill the ( Flaunt 40 Radioactive Isotopes in Medicine front and bark body scans oi patient were made using radioactive Assessment Section I I ) LA it ( Predicting it ! ihr ( a . Explaining Him tan i ! I HINT ?

Vocabulary Skill Greek Word Origins what , thy i ii ' and i ( ii ! and ' i . i ' i min ( Reviewing Key Concepts HINT . Identifying did ( i ill Ui ! HINT Interpreting Photographs photo in ' in ' what . in am ! in ' i i ( ii ?

i ! Ili ) in i . Applying Him ( iii twin new Suppose you ( ould go ' back in time to interview Henri on MINT a . Listing ) oi the day , his , his perspective , write an of the . and Contrasting ( the . iii ul ' 163 . Relating Cause and Li of Introduction to Atoms Key Concepts . theory as strict of models on . As more was collected . the and models were revised . A the containing and . it is surrounded by region of electron . Key Terms atom ' Organ the Elements Key Concepts ) a pattern in elements lay mass . I The of an element can lie predicted from its lU ( in the periodic table . Thu periodic table each atomic number . name , and atomic . Key Terms atomic mass table period Metals Key Concepts , in metals luster . ductility , and Th tends to left to right the table . Scientists make elements by limiting , nuclear particle crash into on another . Key Terms malleable alkali metal ductile alkaline metal transition metal particle thermal electrical reactivity 1640 The organization of the periodic table is based on the properties at the demerits and the structure of atoms . Inert Gases , and Key Concepts , Must are prior at and electric current . are dull and . The inert tend he . The must useful property til the is their varying In electric current . Key Terms nonmetal gas diatomic halogen Radioactive Elements Key Concepts I In the French scientist Henri decay quite accident while a mineral uranium . I Natural radioactive decay cam produce alpha particles . particles . and rays . Use radioactive isotopes include tracing the ( and industrial . and diagnosing and treating . Key Terms radioactive decay particle beta particle gam ma tracer Radioactive nucleus protons and neutrons lost Alpha particle

Review and Assessment . For Visit Web ( ode Target Reading Skill . solid are in Preview Visuals the ( ai gum Ur ! Jud mam ' to that Figure 37 Cu ( Add i I ' I ( Ire rum an . sets dull and A lli ( Radioactive Decay that ' fa , amt . and are i ' show , i . Complete the following sentences so that your answers dearly explain the key terms . Why are there three similar diagram ?

What do the arrows show ?

urban are of nut . Dmitri the first mur periodic , is Reviewing Key Terms . A is high thermal in Choose the letter of the best answer . INT . The number an ' Ur im ' nu , by . number properties , protons . and radon share the property . radioactivity , which mum . INT . The in the table are ' gin Science ) News leper ! you are an ! article for a space magazine about the life ! cycle of a star . Which elements are produced . the , the group th ! contains ' 93 INT that are most is the ?

alkali metals . alkaline earth metals . carbon family . inert gases . III Elements and the Table 9165 Review and Assessment Checking Concepts 11 What about the alum did Rutherford from his train ?

114 How do two isotopes from another ?

How are ?

the periodic to lind the atomic mass INN . the to name two elements that have properties to those of chlorine Mil ) 01 ' the ' IO . and poor conductor and a at room temperature ?

16 What properties of ) them ?

17 . Comparing and Contrasting List the kinds of that links up their their in an atom . king Critically 18 . Applying Below Is at square taken from the . the ul given labeled item . 28 NI 19 . Relating Cause and Effect The atomic mass of iron amu . Why value a ?

20 . Predicting Using the periodic , tron . or ' must . Explain . 21 . Inferring materials us in chips them switches that turn electricity on anti oft ?

165 Applying Skills Use the diagram to answer Questions . drum of . Mass Number 90 92 Atomic Number 22 . Reading Graphs What do Ihr ( In the ' axis and ) tell atomic the nuclei of ?

23 . Interpreting Data How arc in the ?

How isotopes of art ?

24 . Classifying What type ( I hemming 234 ?

How do you know ?

25 . Interpreting Diagrams how is into 26 . Inferring do you know from the diagram that ! iu ?

27 Posing Questions What would you to ' in order In graph to show how 226 changes ?

Standards Investigation ( Assessment the chart showing the you . Be ready to discuss which properties are common to all ) tIll of you cuuld not test . List all the properties that he used to out whether an element is metal .

Standards Practice Choose the letter of the best answer . Why is the mass of a carbon atom greater than the total of its and ?

A The mass of a proton is greater than the mass of an election . I A proton is positively charged and an electron is negatively charged . Most of the atom volume is the shaped cloud of electrons . On or more neutrons in the nucleus add mass to the atom . Elements that are shiny conductive solids at room temperature are likely to be as which of the following ?

A metals I inert use the diagram below to answer Question . protons . neutrons . What isotope does the diagram represent ?

A I . Which of aluminum makes it a suitable metal for soft drink cans ?

A It has good electrical conductivity . I It can he hammered into a thin sheet ( It can be drawn into long wires ( ductility ) It can reflect light ) Success it Trucker Orin Use the table below no answer Questions . What element has an atomic number of 18 ?

A hydrogen oxygen argon . An atom of has neutrons . What is the total number of other subatomic particles in this atom ?

A protons and electrons protons and electrons protons and 10 electrons 19 protons and 19 electrons . Which elements are inert gases ?

A oxygen . and neon , chlorine . and argon oxygen . and chlorine neon and argon , I Idea . Suppose scientists synthesized in new element with the atomic number . Use what you about the organization of the periodic table to predict the properties of this new element . 167

Introduction to Physical Science Scientists investigate the natural world by posing questions . developing hypotheses . designing experiments . analyzing data . drawing conclusions . and communicating results . what do physical scientists study ?

role do models , theories , and laws play in science ?

Why do scientists use a standard system of measurement ?

should you do if a lab accident occurs ?

Chapter The Nature of Matter Chemistry is the study of the properties of matter and how matter changes . kinds of properties are used to describe matter ?

is a physical change ?

How is chemical energy related to chemical change ?

Chapter Solids , Liquids , and Gases In solids , the particles vibrate in closely , fixed positions . In liquids . the particles are loosely connected and collide with one another . In gases , the particles are free to move independently . How can you describe the behavior of particles in a solid ?

What happens to a substance during changes between liquid and gas ?

How are the volume , temperature , and pressure of a gas related ?

Chapter Elements and the Periodic Table The organization of the periodic table is based on the properties of the elements and reflects the structure of atoms . How are the elements organized in the modern periodic table ?

How does the reactivity of metals change across the periodic table ?

What are the properties of and inert gases ?

in lli BIG Ideas Sue and Juanita are throwing a big party for their friends They purchase 100 bottles of seltzer ( water with carbon dioxide gas in it ) fill their car trunk with all the bottles . and drive home . Since the party wo be until tomorrow , they decide to leave the seltzer in the car overnight . The next morning , they open the car trunk and discover that all the seltzer has They bring the bottles inside the house and let them warm up until the seltzer is liquid again . At the party . one of the guests , Ben , asks if he can make an fashioned chocolate soda to drink . He fills a glass of the way with seltzer , adds some dark brown chocolate syrup and white milk . and stirs it thoroughly . When he done , the chocolate soda has a light brown color . Hi , Ii the mass of all the seltzer that Sue and Juanita bought was 200 kilograms , what was the density of the ( Chapter i ) The main component of seltzer is water . Water is a compound made up of the elements hydrogen and oxygen . gIL which class of elements does oxygen . 200 gIL belong to ?

Chapter ) is is . I . Ben chocolate soda is an example of ain ) ir . a ( Chapter ) Summary Write a paragraph that summarizes the changes that the seltzer in the description above went through . Did the seltzer undergo a chemical change ?

Explain . heterogeneous mixture is . homogeneous mixture element compound . As the frozen seltzer melted into a liquid , what happened to the freedom of motion of the water molecules ?

Chapter ) a . It increased . It decreased . It stayed the same . It became zero . 169