how are billiards bottles - irion-isd.org · you ride in. figure 1 the various properties of metals...

How AreBilliards & Bottles

Connected?

U N I T55 Diversity of Matter

How AreBilliards & Bottles

Connected?

604

SCIENCE CONNECTIONSCIENCE CONNECTION

POLYMERS Plastics are polymers—long molecules made up of smaller unitscalled monomers. By using different monomers, it’s possible to create plasticswith different characteristics. Explore your home or school and make a list of plas-tic items. How do the physical characteristics of different plastics—hardness,flexibility, and so forth—relate to their function? Using your list as a reference,write a description of one part of your day, identifying all the plastics you use.

Billiards, a popular table game of the 1800s, used balls carved from ivory.In the 1860s, an ivory shortage prompted one billiard-ball manufac-

turer to offer a reward of $10,000 to anyone who could come up with a suit-able substitute. In an attempt to win the prize, an inventor combined cer-tain organic compounds, put them into a mold, and subjected them to heatand pressure. The result was a hard, shiny lump that sparked a major newindustry—the plastics industry. By the mid-1900s, chemists had inventedmany different kinds of moldable plastic. Today, plastic is made into count-less products—everything from car parts to soda bottles.

606

It takes many different elements tobuild an airplane like this one.Some of those elements are met-

als, some are nonmetals, and someare metalloids. Each element has dis-tinct properties. Knowing the proper-ties of elements allows you to usethem in a variety of practical ways—from treating diseases to building anairplane. This chapter will describegroups of elements and help youlearn how they are related.

What do you think?Science Journal Look at the picturebelow with a classmate. Discuss whatyou think this might be. Here’s a hint: The gas in the tubes stands apartfrom the crowd. Write your best guessin your Science Journal.

Elements and Their Properties

2020

607

It may be surprising to you that every known physi-cal object is made from one or more of 115 known

elements. When they are not bonded to atoms ofother elements, the atoms of an element have spe-cific, identifiable properties. In this activity, you’ll

observe how heated atoms of elements absorb energy and then in a short timerelease the absorbed energy, which you see as colored light.

Observe colorful clues1. Using tongs, carefully hold a clean paper clip

in the hottest part of a lab burner flame for 45 seconds.

2. Dip the hot paper clip into a solution of copper(II) sulfate.

3. Using the tongs with the same paper clip, repeat step 1, observingany color change.

4. Repeat all three steps using solutionsof strontium chloride and sodium chloride with clean tongs.

Observe 1. Which element—chlorine or strontium—was responsible for the color

observed when strontium chloride was placed in the flame? How do youknow?

2. In your Science Journal devise a plan to determine whether copper or sulfate was responsible for the color in step 2.

EXPLOREACTIVITY

607607607

Making a Classify Study Fold Make the following Foldable to help you classify and organize objects into groups based on theircommon features.

1. Place a sheet of paper in front of you so the longside is at the top. Fold the paper in half from the leftside to the right side. Fold top to bottom and crease.Then unfold.

2. Through the top thickness of paper, cut along the middle fold line to form two tabs as shown.

3. Label the tabs Metals and Nonmetals as shown.

4. Before you read the chapter, list all the metal and nonmetal elements you know on the frontof the tabs. As you read the chapter, check your list and make changes as needed.

FOLDABLESReading & StudySkills

FOLDABLESReading & Study Skills

Metals Nonmetals

608 CHAPTER 20 Elements and Their Properties

Metals S E C T I O N

Properties of Metals The first metal used about 6,000 years ago was gold. The use

of copper and silver followed a few thousand years later. Thencame tin and iron. Aluminum wasn’t refined until the 1800sbecause it must go through a much more complicated refiningprocess that earlier civilizations had not yet developed.

In the periodic table, metals are elements found to the left ofthe stair-step line. In the table on the inside back cover of yourbook, the metal element blocks are colored blue. Metals usuallyhave common properties—they are good conductors of heat andelectricity, and all but one are solid at room temperature. Mer-cury is the only metal that is not a solid at room temperature.Metals also reflect light. This is a property called luster. Metalsare malleable (MAH lee uh bul), which means they can be ham-mered or rolled into sheets, as shown in Figure 1A. Metals arealso ductile, which means they can be drawn into wires like theones shown in Figure 1B. These properties make metals suitablefor use in objects ranging from eyeglass frames to computers tobuilding structures.

� Describe the properties of a typicalmetal.

� Identify the alkali metals andalkaline earth metals.

� Differentiate among three groupsof transition elements.

Vocabulary metal metallic bondingmalleable radioactive elementductile transition element

Metals are a part of your everydaylife—from electric cords to the carsyou ride in.

Figure 1The various properties ofmetals make them useful.

Metals, like the oneshown, can be ham-mered into thin sheets.What is one use for a sheetof metal?

Metals can be drawn into wires, likethe wire that is being used here. What isthis property of metals called?

Ionic Bonding in Metals The atoms of metals generallyhave one to three electrons in their outer energy levels. In chem-ical reactions, metals tend to give up electrons easily becausethey are close to having an empty outer energy level. When met-als combine with nonmetals, the atoms of the metals tend tolose electrons to the atoms of nonmetals, forming ionic bonds,as shown in Figure 2. Both metals and nonmetals become morechemically stable when they form ions. They take on the elec-tron structure of the nearest noble gas.

Metallic Bonding Another type of bonding, neither ionicnor covalent, occurs among the atoms in a metal. In metallicbonding, positively charged metallic ions are surrounded by acloud of electrons. Outer-level electrons are not held tightly tothe nucleus of an atom. Rather, the electrons move freely amongmany positively charged ions. As shown in Figure 3, the elec-trons form a cloud around the ions of the metal.

The idea of metallic bonding explains many of the proper-ties of metals. For example, when a metal is hammered into asheet or drawn into a wire, it does not break because the ions arein layers that slide past one another without losing their attrac-tion to the electron cloud. Metals are also good conductors ofelectricity because the outer-level electrons are weakly held.

Why do metals conduct electricity?

Look at the periodic table inside the back cover of yourbook. How many of the elements in the table are classified asmetals? All of the blue-shaded boxes represent metals. Except forhydrogen, all the elements in Groups 1 through 12 are metals, aswell as the elements under the stair-step line in Groups 13through 15. You will learn more about metals in some of thesegroups throughout this chapter.

SECTION 1 Metals 609

Metal Nonmetal

Ag�

Ag�

Ag�

Ag�

Ag�

Ag�

Ag�

Ag�

Ag�

Ag�

Ag�

Ag�

Ag�

Figure 2 Metals can form ionic bonds withnonmetals.

Figure 3 In metallic bonding, theelectrons represented bythe cloud are not attachedto any one silver ion. Thisallows them to move andconduct electricity.

The Alkali Metals The elements in Group 1 of the periodic table are the alkali

(AL kuh li) metals. Like other metals, Group 1 metals are shiny,malleable, and ductile. They are also good conductors of heatand electricity. However, they are softer than most other metals.The alkali metals are the most reactive of all the metals. Theyreact rapidly—sometimes violently—with oxygen and water, asshown in Figure 4. Because they combine so readily with otherelements, alkali metals don’t occur in nature in their elementalform and are stored in substances that are unreactive, such asan oil.

Each atom of an alkali metal has one electron in its outerenergy level. This electron is given up when an alkali metal com-bines with another atom. As a result, the alkali metal becomes apositively charged ion in a compound such as sodium chloride,NaCl, or potassium bromide, KBr.

Alkali metals and their compounds have many uses. You andother living things need potassium and sodium compounds tostay healthy. Doctors use lithium compounds to treat bipolardepression. The lithium keeps chemical levels that are importantto mental health within a narrow range. The operation of somephotocells depends upon rubidium or cesium compounds.Francium, the last element in Group 1, is extremely rare andradioactive. A radioactive element is one in which the nucleusbreaks down and gives off particles and energy. Francium can befound in uranium minerals, but only 25 g to 30 g of franciumare in all of Earth’s crust at one time.


Potassiumreacts strongly inwater.

1H

3Li

11Na

19K

37Rb

55Cs

87Fr

The Alkali Metals

Figure 4Alkali metals are very reactive.

Sodium will burnin air if it is heated.

The Alkaline Earth Metals The alkaline earth metals make up Group 2 of the periodic

table. Like most metals, these metals are shiny, malleable, andductile. They are also similar to alkali metals in that they com-bine so readily with other elements that they are not found asfree elements in nature. Each atom of an alkaline earth metal hastwo electrons in its outer energy level. These electrons are givenup when an alkaline earth metal combines with a nonmetal. As aresult, the alkaline earth metal becomes a positively charged ionin a compound such as calcium fluoride, CaF2.

Fireworks and Other Uses Magnesium metal is one of themetals used to produce the brilliant white color in fireworks likethe ones in Figure 5. Compounds of strontium produce thebright red flashes. Magnesium’s lightness and strength accountfor its use in cars, planes, and spacecraft. Magnesium also is usedin compounds to make such things as household ladders andbaseball and softball bats. Most life on Earth depends uponchlorophyll, a magnesium compound that enables plants tomake food. Marble statues and some countertops are made ofthe calcium compound calcium carbonate.

The Alkaline Earth Metals and Your Body Calcium isseldom used as a free metal, but its compounds are needed for life. You may take a vitamin with calcium. Calcium phos-phate in your bones helps make them strong.

The bariumc o m p o u n dBaSO4 is used

to diagnose some digestive disordersbecause it absorbs X-ray radiation well.First, the patient swallows a barium com-pound. Next, an X ray is taken while thebarium compound is going through thedigestive tract. A doctor can then seewhere the barium is in the body. In thisway, doctors can diagnose internal abnor-malities in the body.

Radium, the last element in Group 2,is radioactive and is found associatedwith uranium. It was once used to treatcancers. Today, other radioactive ele-ments that are more readily available arereplacing radium in cancer therapy.

Health

611

4Be

12Mg

20Ca

38Sr

56Ba

88Ra

The Alkaline Earth Metals

Figure 5Alkaline earth metals makespectacular fireworks.

Transition Elements A titanium bike frame and a glowing tungsten lightbulb fila-

ment are examples of objects made from transition elements.Transition elements are those elements in Groups 3 through 12in the periodic table. They are called transition elements becausethey are considered to be elements in transition between Groups1 and 2 and Groups 13 through 18. Look at the periodic tableinside the back cover of your book. Which elements do you thinkof as being typical metals? Transition elements are the mostfamiliar because they often occur in nature as uncombined ele-ments, unlike Group 1 and Group 2 metals which are less stable.

Transition elements often form colored compounds. Thegems in Figure 6 show brightly colored compounds containingchromium. Cadmium yellow and cobalt blue paints are madefrom compounds of transition elements. However, cadmiumand cobalt paints are so toxic that their use is limited.

Iron, Cobalt, and Nickel The first elements in Groups 8,9, and 10—iron, cobalt, and nickel—form a unique cluster oftransition elements. These three sometimes are called the irontriad. All three elements are used in the process to create steeland other metal mixtures.

Iron—the main component of steel—is the most widelyused of all metals. It is the second most abundant metallic ele-ment in Earth’s crust after aluminum. Other metals are addedto steel to give it various characteristics. Some steels containcobalt or nickel. Nickel is added to some metals to give themstrength. Also, nickel is used to give a shiny, protective coatingto other metals.


Discovering What’s in CerealProcedure1. Tape a small, strong

magnet to a pencil at theeraser end.

2. Place some dry, fortified,cold cereal in a plastic bag.

3. Thoroughly crush the cereal.4. Pour the crushed cereal into

a deep bowl and cover itwith water.

5. Stir the mixture for about10 min with your pencil/magnet. Stir slowlyfor the last minute.

6. Remove the magnet andexamine it carefully. Recordyour observations.

Analysis1. What common element is

attracted to your magnet? 2. Why is this element added

to the cereal?

Figure 6The colors of the ruby and emerald are due to the transition elementchromium.

28Ni

27Co

26Fe

The Iron Triad

Copper, Silver, and Gold The main metals in the objects inFigure 7 are copper, silver, and gold—the three elements inGroup 11. Because they are so stable and malleable and can befound as free elements in nature, these metals were once usedwidely to make coins. For this reason, they are known as thecoinage metals. However, because they are so expensive, silverand gold rarely are used in coins anymore. The United Statesstopped using gold in the production of its coins in 1933 andsilver in 1964. Most coins now are made of nickel and copper.

Copper often is used in electrical wiring because of its supe-rior ability to conduct electricity and its relatively low cost. Canyou imagine a world without photographs and movies? Silveriodide and silver bromide break down when exposed to light,producing an image on paper. Consequently, these compoundsare used to make photographic film and paper. Silver and goldare used in jewelry because of their attractive color, relative soft-ness, resistance to corrosion, and rarity.

Why does gold’s relative softness make it a good choice for jewelry?

Zinc, Cadmium, and Mercury Zinc, cadmium, and mer-cury are found in Group 12 of the periodic table. Zinc combineswith oxygen in the air to form a thin, protective coating of zincoxide on its surface. Zinc and cadmium often are used to coat,or plate, other metals such as iron because of this protectivequality. Cadmium is used also in rechargeable batteries.

Mercury is a silvery, liquid metal—the only metal that is aliquid at room temperature. It is used in thermometers, thermo-stats, switches, and batteries. Mercury is poisonous and canaccumulate in the body. People have died of mercury poisoningafter eating fish that lived in mercury-contaminated water.

29Cu

47Ag

79Au

The CoinageMetals

30Zn

48Cd

80Hg

Zinc, Cadmium,and Mercury

Figure 7The coinage metals have many uses.

Gold frequently is usedin jewelry.

Silver is used in compoundsto make photographic materials.

Because gold and silver are soexpensive, copper is more commonin coins.



The Inner Transition Metals The two rows of elements that seem to be disconnected from

the rest on the periodic table are called the inner transition ele-ments. They are called this because like the transition elements,they fit in the periodic table between Groups 3 and 4 in periods6 and 7, as shown in Figure 8. To save room, they are listedbelow the table.

The Lanthanides The first row includes a series of elementswith atomic numbers of 58 to 71. These elements are called thelanthanide series because they follow the element lanthanum.

Lanthanum, cerium, praseodymium, and samarium are usedwith carbon to make a compound that is used extensively by themotion picture industry. Europium, gadolinium, and terbiumare used to produce the colors you see on your TV screen.

The Actinides The second row of inner transition metalsincludes elements with atomic numbers ranging from 90 to 103.These elements are called the actinide series because they followthe element actinium. All of the actinides are radioactive andunstable. Their unstable nature makes researching them diffi-cult. Thorium and uranium are the actinides found in theEarth’s crust in usable quantities. Thorium is used in makingthe glass for high-quality camera lenses because it bends lightwithout much distortion. Uranium is best known for its use innuclear reactors and in weapons applications, but one of itscompounds has been used as photographic toner, as well. Morewill be said about these elements at the end of Section 3.

58Ce

59Pr

60Nd

61

Pm

62

Sm

63Eu

64Gd

65Tb

66Dy

67Ho

68Er

69

Tm

70Yb

71Lu

90Th

91Pa

92U

93Np

94Pu

95

Am

96

Cm

97Bk

98Cf

99Es

100

Fm

101

Md

102

No

103Lr

Lanthanide series Actinide seriesFigure 8To save space, the periodic table usually isn’t shown withthe inner transition elements positioned where they should be.Where are the lanthanide andactinide series?

Not all materials minedfrom Earth can be used inthe form they come in. Iron,for example, must berefined from iron ore inlarge blast furnaces. Inthese furnaces, charcoal isburned to create carbonmonoxide gas that com-bines with the oxygen inthe iron ore and carries itaway. Other ways toextract materials from theirores include mixing them insolutions and using electric-ity. Find examples of metalsthat are purified from theirores by these two methods.


Metals in the Crust Earth’s hardened outer layer, called the crust,

contains many compounds and a few uncombinedmetals such as gold and copper. Metals must bemined and separated from their ores, as shown inFigure 9.

Some metals are more abundant in one placethan in another. Most of the world’s platinum isfound in South Africa. Chromium is importantbecause it is used to harden steel, to manufacturestainless steel, and to form other alloys. TheUnited States imports most of its chromium fromSouth Africa, the Philippines, and Turkey.

Ores: Minerals and Mixtures Metals in Earth’s crust thatcombined with other elements are found as ores. Most ores con-sist of a metal compound, or mineral, within a mixture of clayor rock. After an ore is mined from Earth’s crust, the rock is sep-arated from the mineral. Then the mineral often is converted toanother physical form. This step usually involves heat and iscalled roasting. Finally, the metal is refined into a pure form.Later it can be alloyed with other metals.

Removing the waste rock can be expensive. If the cost ofremoving the waste rock becomes greater than the value of thedesired material, the mineral no longer is classified as an ore.

Section Assessment

1. How would you test a piece of palladium tosee whether it is a metal?

2. How does the arrangement of the irontriad differ from the arrangements ofcoinage metals? Of the zinc group?

3. What characteristics are shared by alkalimetals and alkaline earth metals?

4. How do metallic bonds differ from ionicand covalent bonds?

5. Think Critically If X stands for a metal,how can you tell from the following formulas—XCl and XCl2—which compound contains an alkali metal andwhich contains an alkaline earth metal?

6. Interpreting Scientific Illustrations Drawdot diagrams to show the similarity among the chlorides of three alkali metals: lithium chloride, sodium chloride, and potassium chloride. For more help, refer to the ScienceSkill Handbook.

7. Using Percentages Pennies used to be madeof 95 percent copper and 5 percent zinc, andthey each weighed 3.11 g. Today, pennies aremade of copper-plated zinc, and each weighs 2.5 g. A new penny weighs what percent of anold penny? For more help, refer to the MathSkill Handbook.

Figure 9Copper is mined in the UnitedStates at the Bingham CanyonCopper Mine in Utah.


Nonmetals S E C T I O N

� Recognize hydrogen as a non-metal.

� Compare and contrast propertiesof the halogens.

� Describe properties and uses of thenoble gases.

Vocabularynonmetaldiatomic molecule

Nonmetals are not only all aroundyou, they are an essential part ofyour body.

H

Ca

C N OOther elements: 2%

Oxygen: 65%

Hydrogen: 10%Nitrogen: 3%

Calcium: 2%Carbon: 18%

Elements in the Human Body

Figure 10As a percentage of mass, humansare made up of mostly nonmetals.

Properties of Nonmetals Most of your body’s mass is made of oxygen, carbon, hydro-

gen, and nitrogen, as shown in Figure 10. Calcium, a metal, andother elements make up the remaining four percent of yourbody’s mass. Phosphorus, sulfur, and chlorine are among theseother elements found in your body. These elements are classifiedas nonmetals. Nonmetals are elements that usually are gases orbrittle solids at room temperature. Because solid nonmetals arebrittle or powdery, they are not malleable or ductile. Most non-metals do not conduct heat or electricity well, and generally theyare not shiny.

In the periodic table, all nonmetals except hydrogen arefound at the right of the stair-step line. On the table in the insideback cover of your book, the nonmetal element blocks are colored yellow. The noble gases, Group 18, make up the onlygroup of elements that are all nonmetals. Group 17 elements,except for astatine, are also nonmetals. Other nonmetals, found in Groups 13 through 16, will be discussed later.

SECTION 2 Nonmetals 617

Bonding in Nonmetals The electrons in most nonmetalsare strongly attracted to the nucleus of the atom. So, as a group,nonmetals are poor conductors of heat and electricity.

Most nonmetals can form ionic and covalent compounds.Examples of these two kinds of compounds are shown in Figure 11.

When nonmetals gain electrons from metals, the nonmetalsbecome negative ions in ionic compounds. An example of suchan ionic compound is potassium iodide, KI, which often isadded to table salt. KI is formed from the nonmetal iodine andthe metal potassium. On the other hand, when bonded withother nonmetals, atoms of nonmetals usually share electrons toform covalent compounds. An example is ammonia, NH3, thestrong, unpleasant-smelling compound you notice when youopen a bottle of some household cleaners.

Hydrogen If you could count all the atoms in the universe, you would

find that about 90 percent of them are hydrogen. Most hydrogenon Earth is found in the compound water. The word hydrogen isderived from the Greek term for “water forming.” When water isbroken down into its elements, hydrogen becomes a gas madeup of diatomic molecules. A diatomic molecule consists of twoatoms of the same element in a covalent bond.

Hydrogen is highly reactive. A hydrogen atom has a singleelectron, which the atom shares when it combines with othernonmetals. For example, hydrogen burns in oxygen to formwater, H2O, in which hydrogen shares electrons with oxygen.

Hydrogen can gain an electron when it combines with alkaliand alkaline earth metals. The compounds formed are hydrides,such as sodium hydride, NaH.

What is a diatomic molecule?

O OC

1H

Hydrogen

Figure 11Nonmetals form ionic bonds withmetals and covalent bonds withother nonmetals.

Pb SSPb O OC

Lead and sulfur bond ionically to form leadsulfide, PbS, also known as galena.

Carbon and oxygen can bond covalently toform carbon dioxide, CO2.

The Halogens Halogen lights contain small amounts of bromine or iodine.

These elements, as well as fluorine, chlorine, and astatine, arecalled halogens and are in Group 17. They are very reactive intheir elemental form, and their compounds have many uses. Asshown in Figure 12, fluorides are added to toothpastes and tocity water systems to prevent tooth decay, and chlorine com-pounds are added to water to disinfect it.

Because an atom of a halogen has seven electrons in its outerenergy level, only one electron is needed to complete this energylevel. If a halogen gains an electron from a metal, an ionic com-pound, called a salt, is formed. In the gaseous state, the halogensform reactive diatomic covalent molecules and can be identifiedby their distinctive colors. Chlorine is greenish yellow, bromineis reddish orange, and iodine is violet.

Fluorine is the most chemically active of all elements.Hydrofluoric acid, a mixture of hydrogen fluoride and water, isused to etch glass and to frost the inner surfaces of lightbulbs.


Identifying Chlorine Compounds in YourWaterProcedure

1. In three labeled test tubes,obtain 2 mL of chlorinestandard solution, distilledwater, and drinking water.

2. Carefully add five drops ofsilver nitrate solution toeach and stir. WARNING:Avoid contact with the silvernitrate solution.

Analysis1. Which solution will definitely

show a presence of chlorine?How did this result compareto the result with distilledwater?

2. Which result most resembledyour drinking water?

Fluoride compounds are used in toothpaste to prevent tooth decay.

9F

17Cl

35Br

53I

85At

The Halogens

Figure 12The halogens have many uses.

Chlorine compounds are used in pools to disinfect the water.

SECTION 2 Nonmetals 619

Uses of Halogens The odor you sometimes smell near aswimming pool is chlorine. Chlorine compounds are used todisinfect water. Chlorine, the most abundant halogen, isobtained from seawater at ocean-salt recovery sites like the onein Figure 13. Household and industrial bleaches used to whitenflour, clothing, and paper also contain chlorine compounds.

Bromine, the only nonmetal that is a liquid at room temper-ature, also is extracted from compounds in seawater. Otherbromine compounds are used as dyes in cosmetics.

Iodine, a shiny purple-gray solid at room temperature, isanother halogen obtained from seawater. When heated, iodinechanges directly to a purple vapor. The process of a solid chang-ing directly to a vapor without forming a liquid is called subli-mation, as shown in Figure 14. Iodine is essential in your dietfor the production of the hormone thyroxin and to prevent goi-ter, an enlarging of the thyroid gland in the neck.

What is sublimation?

Astatine is the last member of Group 17. It is radioactive andrare, but has many properties similar to those of the other halo-gens. There are no known uses due to its rarity.

Compounds called chloro-fluorocarbons are used inrefrigeration systems. Ifreleased, these compoundsdestroy ozone in the atmo-sphere. The ozone protectsyou from some of the harm-ful rays from the Sun. Findthe advantages and disad-vantages of these com-pounds. Write your answerin your Science Journal.

Figure 13This ocean-salt recovery siteuses evaporation to separatethe halogen compounds fromthe water so the salts can berefined further.

Figure 14Frozen carbon dioxide, or dry ice,is used to make inexpensive,visible gas for theatrical produc-tions. The carbon dioxide isbrought out as a solid, then itsublimes as shown here.

The Noble Gases The noble gases exist as isolated atoms. They are stable

because their outermost energy levels are full. No naturallyoccurring noble gas compounds are known, but several com-pounds of xenon and krypton with fluorine have been createdin a laboratory.

The stability of noble gases is what makes them useful. Inaddition, the light weight of helium makes it useful in lighter-than-air blimps and balloons. Neon and argon are used in “neonlights” for advertising. Argon and krypton are used in electriclightbulbs to produce light in lasers, as seen in Figure 15.


Section Assessment

1. What are two ways in which hydrogencombines with other elements?

2. Rank the following nonmetals from lowestnumber of electrons in the outer level tohighest: Cl�, H�, He, and H. What prop-erty of noble gases makes them useful?

3. How are solid nonmetals different fromsolid metals?

4. How can you tell that a gas is a halogen?

5. Think Critically What is the process of asolid changing directly into a vapor? Whichelement undergoes this process?

6. Interpreting Data Within the following compounds, identify the nonmetal and list itsoxidation number: MgO, NaH, AlBr3, and FeS.For more help, refer to the Science Skill Handbook.

7. Communicating In your Science Journal,write a paragraph explaining why nonmetalsform ionic and covalent compounds, but notmetallic bonds. Give some examples of ionic and covalent bonds. For more help, refer to the Science Skill Handbook.

Figure 15Noble gases are used to producespectacular laser light shows.

10Ne

2He

18Ar

36Kr

54Xe

86Rn

Noble Gases

ACTIVITY 621

Compare your results with those of other students. For more help, refer to the Science Skill Handbook.

What type is it?

4. Repeat step 3 for each sample.

5. Test the conductivity of each element bytouching the electrodes of the conductivitytester to a sample. If the bulb lights, theelement conducts electricity. Record yourresults.

Conclude and Apply1. Locate each element you used on the

periodic table. Compare your results withwhat you would expect from an element inthat location.

2. Locate palladium, Pd, on the periodic table.Use the results you obtained during the activity to predict some of the properties of palladium.

3. Infer why some elements might show properties of metals as well as properties of nonmetals.

Suppose you want anelement for a certain

use. You might be able touse a metal but not anonmetal. In this activity,you will test several met-als and nonmetals andcompare their properties.

What You’ll InvestigateHow can you use properties to distinguish metalsfrom nonmetals?

Materialssamples of C, Mg, Al, conductivity tester

S, and Sn spatuladishes for the samples small hammer

Goals� Observe physical properties.� Test the malleability of the materials.� Identify electrical conductivity in the given

materials.

Safety Precautions

Procedure1. Prepare a table in your Science Journal like

the one shown.

2. Observe and record the appearance of eachelement sample. Include its physical state,color, and whether it is shiny or dull.

3. Remove a small sample of one of the ele-ments. Place it on a hard surface chosen byyour teacher. Gently tap the sample with ahammer. The sample is malleable if it flattenswhen tapped and brittle if it shatters. Recordyour results.

Element Appearance Malleable Electrical Shinyor Brittle Conductivity or Dull

Carbon

Magnesium

Aluminum

Sulfur

Tin

Observing Properties

Mixed GroupsS E C T I O N

� Distinguish among metals,nonmetals, and metalloids.

� Describe the nature of allotropes.� Recognize the significance of

differences in crystal structure incarbon.

� Understand the importance ofsynthetic elements.

Vocabularymetalloidallotropesemiconductortransuranium element

The elements in mixed groups affectyour life every day, because they arein everything from the computer youuse to the air you breathe.

Figure 16Aluminum is used frequently inthe construction of airplanesbecause it is light and strong.

5B

13Al

31Ga

49In

81Tl

The Boron Group

Properties of Metalloids Can an element be a metal and a nonmetal? In a sense, some

elements called metalloids are. Metalloids share unusual charac-teristics. Metalloids can form ionic and covalent bonds withother elements and can have metallic and nonmetallic proper-ties. Some metalloids can conduct electricity better than mostnonmetals, but not as well as some metals, giving them thename semiconductor. With the exception of aluminum, themetalloids are the elements in the periodic table that are locatedalong the stair-step line. The mixed groups—13, 14, 15, 16, and17—contain metals, nonmetals, and metalloids. Group 17, thehalogens, were discussed in Section 2.

The Boron Group Boron, a metalloid, is the first element in Group 13. If you

look around your home, you might find two compounds ofboron. One of these is borax, which is used in some laundryproducts to soften water. The other is boric acid, a mild antisep-tic. Boron also is used as a grinding material and as boranes,which are compounds used for jet and rocket fuel.

Aluminum, a metal in Group 13, is the most abundant metalin Earth’s crust. It is used in soft-drink cans, foil wrap, cookingpans, and as siding. Aluminum is strong and light and is used inthe construction of airplanes such as the one in Figure 16.


SECTION 3 Mixed Groups 623

6C

14Si

32Ge

50Sn

82Pb

The Carbon Group

The Carbon Group Each element in Group 14, the carbon family, has four elec-

trons in its outer energy level, but this is where much of the sim-ilarity ends. Carbon is a nonmetal, silicon and germanium aremetalloids, and tin and lead are metals. Carbon occurs as an ele-ment in coal and as a compound in oil, natural gas, and foods.Carbon in these materials can combine with oxygen to producecarbon dioxide, CO2. In the presence of sunlight, plants utilizeCO2 to make food. Carbon compounds, many of which areessential to life, can be found in you and all around you. Allorganic compounds contain carbon, but not all carbon com-pounds are organic.

Silicon is second only to oxygen in abundance in Earth’scrust. Most silicon is found in sand, SiO2, and almost all rocksand soil. The crystal structure of silicon dioxide is similar to thestructure of diamond. Silicon occurs as two allotropes. Allotropes,which are different forms of the same element, have differentmolecular structures. One allotrope of silicon is a hard, graysubstance, and the other is a brown powder.

What are allotropes?

Silicon is the main component in semiconductors—ele-ments that conduct an electric current under certain conditions.Many of the electronics that you use every day, like the computerin Figure 17A, need semiconductors to run. Germanium, theother metalloid in the carbon group, is used along with silicon inmaking semiconductors. Tin is used to coat other metals to pre-vent corrosion, like the tin cans in Figure 17B. Tin also is com-bined with other metals to produce bronze and pewter. Lead wasused widely in paint at one time, but because it is toxic, lead nolonger is used.

Figure 17Elements in Group 14 havemany uses.

Silicon is used to make the chips thatallow this computer to run.

These tin cans are made ofsteel with a tin coating.


Figure 18Three allotropes of carbon aredepicted here. What geometricshapes make up each allotrope?

Graphite Diamond

Allotropes of Carbon What do the diamond in a diamondring and the graphite in your pencil have in common? They areboth carbon. Diamond, graphite, and buckminsterfullerene,shown in Figure 18, are allotropes of an element.

A diamond is clear and extremely hard. In a diamond, eachcarbon atom is bonded to four other carbon atoms at the ver-tices, or corner points, of a tetrahedron. In turn, many tetra-hedrons join together to form a giant molecule in which theatoms are held tightly in a strong crystalline structure. Thisstructure accounts for the hardness of diamond.

Graphite is a black powder that consists of hexagonal layersof carbon atoms. In the hexagons, each carbon atom is bondedto three other carbon atoms. The fourth electron of each atom isbonded weakly to the layer next to it. This structure allows thelayers to slide easily past one another, making graphite an excel-lent lubricant. In the mid 1980s, a new allotrope of carboncalled buckminsterfullerene was discovered. This soccer-ball-shaped molecule, informally called a buckyball, was named afterthe architect-engineer R. Buckminster Fuller, who designedstructures with similar shapes.

In 1991, scientists were able to use the buckyballs to synthe-size extremely thin, graphitelike tubes. These tubes, called nan-otubes, are about 1 billionth of a meter in diameter. That meansyou could stack tens of thousands of nanotubes just to get thethickness of one piece of paper. Nanotubes might be used some-day to make computers that are smaller and faster and to makestrong building materials.

Research Visit the Glencoe Science Web site at science.glencoe.comfor more information aboutbuckminsterfullerene.Communicate to your classwhat you learn.

Buckminsterfullerene

http://www.science.glencoe.com

The Nitrogen Group The nitrogen family makes up Group 15. Each element has

five electrons in its outer energy level. These elements tend toshare electrons and to form covalent compounds with other ele-ments. Nitrogen often is used to make nitrates and ammonia,NH3, both of which are used in fertilizers. Nitrogen is the fourthmost abundant element in your body. Each breath you take isabout 80 percent gaseous nitrogen in the form of diatomic mol-ecules, N2. Yet you and other animals and plants can’t use nitro-gen in its diatomic form. The nitrogen must be combined intocompounds, such as nitrates—compounds that contain thenitrate ion, NO3

–.

7N

15P

33As

51Sb

83Bi

The NitrogenGroup

Math Skills Activity

Using Circle Graphs to Illustrate Data

Practice Problems

Example Problem Oxygen, the predominant element in Earth’s crust, makes up

approximately 46.6 percent of the crust. If you were to show this information on a circle graph, how many degrees would be used to represent oxygen?

Solution

This is what you know: oxygen � 46.6%circle contains 360°

This is what you want to find: the part of 46.6 to 360°

This is the equation you need to use: �

Solve the equation for x: x � � 167.76° or 168°

Check your answer by dividing your answer by 360, then multiplying by 100.

46.6 � 360°��

100

x�360°

46.6�100

1. The percentages of remaining elementsin Earth’s crust are: silicon, 27.7;aluminum, 8.1; iron, 5.0; calcium, 3.6;sodium, 2.8; potassium, 2.6; magne-sium, 2.1; and other elements, 1.5.Illustrate in a circle graph.

2. The approximate percentages of theelements in the body are: oxygen, 65;carbon, 18; hydrogen, 10; nitrogen, 3;calcium, 2; and other elements whichaccount for 2. Illustrate these percent-ages in a circle graph.


For more help, refer to the Math Skill Handbook.

Uses of the Nitrogen Group Phosphorus is a nonmetalthat has three allotropes. Phosphorous compounds can be usedfor many things from water softeners to fertilizers, match heads,and even in fine china. Antimony is a metalloid, and bismuth isa metal. Both elements are used with other metals to lower theirmelting points. It is because of this property that the metal inautomatic fire-sprinkler heads contains bismuth.

Why is bismuth used in fire-sprinkler heads?

The Oxygen Group Group 16 on the periodic table is the oxygen group. You can

live for only a short time without oxygen, which makes up about21 percent of air. Oxygen, a nonmetal, exists in the air asdiatomic molecules, O2. During electrical storms, some oxygenmolecules, O2, change into ozone molecules, O3. Oxygen alsohas several uses in compound form, including the one shown inFigure 19A.

Nearly all living things on Earth need O2 for respiration. Liv-ing things also depend on a layer of O3 around Earth for protec-tion from some of the Sun’s radiation.

The second element in the oxygen group is sulfur. Sulfur is anonmetal that exists in several allotropic forms. It exists asdifferent-shaped crystals and as a noncrystalline solid. Sulfurcombines with metals to form sulfides of such distinctive colorsthat they are used as pigments in paints.

The nonmetal selenium and two metalloids—tellurium andpolonium—are the other Group 16 elements. Selenium is themost common of these three. This element is one of several thatyou need in trace amounts in your diet. Many multivitaminscontain this nonmetal as an ingredient. But selenium is toxic iftoo much of it gets into your system. Selenium also is used inphotocopiers like the one in Figure 19B.


8O

16S

34Se

52Te

84Po

The OxygenGroup

Figure 19Group 16 compounds havea variety of uses.

Solutions of hydrogen per-oxide, H2O2, are used to cleanminor wounds.

Selenium isused in xerographyto make photo-copies.

Synthetic ElementsIf you made something that always fell apart, you might

think you were not successful. However, nuclear scientists arelearning to do just that. By smashing existing elements with par-ticles accelerated in a heavy ion accelerator, they have been suc-cessful in creating elements not typically found on Earth. Exceptfor technetium 43 and promethium 61, each synthetic elementhas more than 92 protons.

Bombarding uranium with protons can make neptunium,element 93. Half of the synthesized atoms of neptunium disinte-grate in about two days. This may not sound useful, but whenneptunium atoms disintegrate, they form plutonium. Thishighly toxic element has been produced in control rods ofnuclear reactors and is used in bombs. Plutonium also can bechanged to americium, element 95. This element is used inhome smoke detectors such as the one in Figure 20. In smokedetectors, a small amount of americium emits harmless, chargedparticles. An electric plate in the smoke detector attracts some ofthese charged particles. When a lot of smoke is in the air, itinterferes with the electric current, which immediately sets offthe alarm in the smoke detector.

Transuranium Elements Elements having more than 92 protons, the atomic number of uranium, are called trans-uranium elements. These elements do not belong exclusively tothe metal, nonmetal, or metalloid group. These are the elementstoward the bottom of the periodic table. Some are in theactinide series, and some are on the bottom row of the mainperiodic table. All of the transuranium elements are syntheticand unstable, and many of them disintegrate quickly.


92U

The Transuranium Elements

Figure 20The americium used in smokedetectors is a synthetic elementthat has saved lives.

Americium-241

CurrentBattery

Smokeparticle

+

–

Smoke detector

Smoke detector


Some elements, such as gold,silver, tin, carbon, copper, andlead, have been known and

used for thousands of years. Mostothers were discovered much morerecently. Even at the time of theAmerican Revolution in 1776, only24 elements were known. The timeline below shows the dates of discovery of selected elements,ancient and modern.

Ag - SILVERFound in tombs

dating to 4000 B.C.

A.D. 1774Cl - CHLORINE

Pale green,toxic gas

Au - GOLDPrized since the

Stone Age

1817Cd - CADMIUM

Used to color yellowand red paint

A.D. 2000

1898Ne - NEON

Glows whenelectricity flows

through it

1900Rn - RADON

Radioactive gas thatmay cause cancer

1952Es - EINSTEINIUM

Radioactive gas namedafter Albert Einstein

1981–1996Bh- BOHRIUM, Uun - UNUNNILIUMElements isolated by a heavy ion

accelerator such as the UNILAC, below

1898Po - POLONIUM and

Ra - RADIUMRadioactive elementsdiscovered by Marie

and Pierre Curie

10,000 B.C. A.D. 1700

A.D. 1800

A.D. 1900

1825Al - ALUMINUMMost abundant

element in Earth’s crust

1868He - HELIUM

Lighter-than-air gasused to fill balloons

Figure 21

VISUALIZING THE DISCOVERY OF ELEMENTS

Why make elements? Figure 21 shows when some of theelements were discovered throughout history. The processesused to discover these elements have varied widely. The mostrecently discovered elements are synthetic. By studying how thesynthesized elements form and disintegrate, you can gain anunderstanding of the forces holding the nucleus together. Whenthese atoms disintegrate, they are said to be radioactive.

Radioactive elements can be useful. For example, tech-netium’s radioactivity makes it ideal for many medical applica-tions. At this time, many of the synthetic elements last onlysmall fractions of seconds after they are constructed and can bemade only in small amounts. However, the value of applicationsthat might be discovered easily could offset their costs.

Seeking Stability Element 114, discovered in 1999, appearsto be much more stable than most synthetic elements of its size.It lasted for 30 s before it broke apart. This may not seem likelong, but it lasts 100,000 times longer than an atom of element112. Perhaps this special combination of 114 protons and 175neutrons allows the nucleus to hold together despite the enor-mous repulsion between the protons.

In the 1960s, scientists theorized that stable synthetic ele-ments exist. Finding one might help scientists understand howthe forces inside the atom work. Perhaps someday you’ll readabout some of the everyday uses this discovery has brought.


Section Assessment

1. Why are Groups 14 and 15 better represen-tatives of mixed groups than Groups 13 andGroup 16?

2. Describe how the allotropes of silicon differin appearance.

3. How is an element classified as a trans-uranium element?

4. What type of structure does a diamondhave? Describe how you would build amodel of this.

5. Think Critically Graphite and a diamondare both made of the element carbon. Whyis graphite a lubricant and diamond thehardest gem known?

6. Concept Mapping Make a concept map forallotropes of carbon using the terms graphite,diamond, buckminsterfullerene, sphere, hexagon,and tetrahedron. For more help, refer to theScience Skill Handbook.

7. Using a Computerized Card Catalog Somepeople are concerned about the use of radio-active elements, such as americium, in smokedetectors and other products. Research smokedetectors and radioactive elements using a com-puterized card catalog. Summarize what youlearn in a table. For more help, refer to theTechnology Skill Handbook.

Data Update For an onlineupdate about synthetic elements, visit the GlencoeScience Web site at science.glencoe.com and select theappropriate chapter.


630

Possible Materialsthin spaghettismall gumdropsthin polystyrene sheetsflat cardboardscissors

Goals� Make a model that will demon-

strate the molecular structure ofgraphite.

� Compare and contrast thestrength of the different bonds ingraphite.

� Infer the relationship betweenbonding and physical properties.

Safety PrecautionsUse care when working with scissorsand uncooked spaghetti.

Often, a lubricant is needed when two metals touch each other. For example, asticky lock sometimes works better with the addition of a small amount of

graphite. What gives this allotrope of carbon the slippery property of a lubricant?

Recognize the ProblemWhy do certain arrangements of atoms in a material cause the material to feel slippery?

Form a HypothesisBased on your understanding of how carbon atoms bond, form a hypothesis about therelationship of graphite’s molecular structure to its physical properties.

Slippery Carbon

Test Your Hypothesis

ACTIVITY 631

Analyze Your Data

Draw Conclusions

5. Read over the experiment tomake sure that all steps arein logical order.

6. Will your model be con-structed with materials thatshow weak and strong attractions?

Do1. Make sure your teacher approves

your plan before you start.

2. Have you selected materials to usein your model that demonstrateweak and strong attractions? Carryout the experiment as planned.

3. Once your model has been con-structed, list any observations thatyou make and include a sketch inyour Science Journal.

Plan1. As a group, agree upon a logical

hypothesis statement.

2. As a group, sequence and list thesteps you need to take to test yourhypothesis. Be specific, describingexactly what you will do at eachstep to make a model of the types ofbonding present in graphite.

3. Remember from Figure 18 thatgraphite consists of rings of six car-bons bonded in a flat hexagon.These rings are bonded to eachother. In addition, the flat rings inone layer are weakly attached toother flat layers.

4. List possible materials you plan to use.

3. How does the bonding of graphitethat you explored in the lab explaingraphite’s lubricating properties?Write your answer in your ScienceJournal.

1. Compare your model with designsand results of other groups.

2. How does your model illustrate twotypes of attractions found in thegraphite structure?

1. Did the results you obtained fromyour experiment support yourhypothesis? Explain.

2. Describe why graphite makes agood lubricant.

3. What kinds of bonds do you think adiamond has?

Explain to a friend why graphite makes agood lubricant and how the two types ofbonds make a difference. For more help,refer to the Science Skill Handbook.

632632

“Nothing in the world gave a glow such

as we had seen.” With these words, two

British chemists recorded their discovery

of neon in 1898. Neon is a noble gas that

emits a spectacular red-orange glow when an

electric current is passed through it. It also

makes up a tiny portion of the air we breathe.

But neon’s presence remained un-

detected until a technology called spec-

troscopy allowed the chemists to view that

“blaze of crimson light” in their lab—a light

that soon lit up the world in fantastical ways.

A neon coffee cup

lights upthe Seattle

night.

Neon has made the world a more colorful place

A neon sign in the making.

Workers carefullytwist the light

tubes into different shapes.

SCIENCEAND

HISTORYSCIENCE

CAN CHANGETHE COURSEOF HISTORY!

632

Signs of ChangePink flamingos, cowboys on bucking

broncos, deep-sea fish afloat in the air—

neon signs make any building or billboard

come alive in a kaleidoscope of colors.

Barely a decade after neon was discovered,

a chemist developed the first neon sign. The

chemist took the air out of a glass tube and

replaced it with neon gas. When the gas

was jolted with electricity, it glowed like a

fiery sunset. The chemist sold the light to a

barber, who hung it over his storefront. By

the 1920s, neon lights were used to adver-

tise everything from cars to diners.

When a touch of mercury is added to

neon, it glows a tropical blue. The other col-

ors seen in “neon lights” actually come from

other noble gases. Krypton, for instance,

glows yellow. Xenon shines like a bluish-

white star.

Other Uses for NeonThe vivid light emitted by neon can pen-

etrate the densest fog, making it a natural

choice for airplane beacons. Neon also is

used to manufacture lasers and television

tubes. Neon definitely helps light up our

lives!Neon lights up a Hong Kong, China night.

CONNECTIONS Design a Sign As a group, brainstorm a new product or business, then design a neon sign to advertise your idea. See if other groups can correctly guess what your sign represents. For more information, visit

science.glencoe.com

Elemental Snobs The noble gases include neon, helium,argon, krypton, xenon, and radon.Scientists called these gases “noble”because that word sometimes implies asnobbish attitude—the perfect descrip-tion for gases that rarely react with other elements. Like the other noblegases, neon is stable.

For an element to be chemically stable, it needs eight electrons in its outer energy level. Neon has eight electrons in its outer shell—so it doesn’t react with other elements because it alreadyhas a complete outer energy level.Although scientists have discovered thatsome noble gases do interact with otherelements, thus far, neon remains aloof.


Section 3 Mixed Groups1. Groups 13 through 16 include metals, non-

metals, and metalloids. Which objects belowappear to be metallic and which appear to be nonmetallic?

2. Allotropes are forms of the same elementhaving different molecular structures.

3. The properties of three forms of carbon—graphite, diamond, and buckminster-fullerene—depend upon the differences intheir crystal structures.

4. All synthetic elements are short-lived. Withtwo exceptions, they have atomic numbersgreater than 92 and are referred to astransuranium elements.

634 CHAPTER STUDY GUIDE

Study GuideChapter 2020

Section 1 Metals1. A typical metal is a hard, shiny solid that,

due to metallic bonding, is malleable,ductile, and a good conductor.

2. Groups 1 and 2 arethe alkali and alka-line earth metals,which have somesimilar and somecontrasting properties. Whyaren’t Group 1 elements typicallyfound in their elemental form?

3. The iron triad, the coinage metals, and theelements in Group 12 are examples of tran-sition elements.

4. The lanthanides and actinides have atomicnumbers 58 through 71 and 90 through103, respectively.

Section 2 Nonmetals1. Nonmetals are typically brittle and dull.

They are also poor conductors of electricity.

2. As a typical nonmetal, hydrogen is a gasthat forms compounds by sharing electronswith other nonmetals and by forming ionicbonds with metals.

3. All the halogens, Group 17, have sevenouter electrons and form covalent and ionic compounds, but each halogen hassome properties that are unlike each ofthe others in the group.

4. The noble gases, Group 18, are elementswhose properties and uses are related totheir chemical stability.

Under the tabs of theFoldable you created,write the common

characteristics of metal elements and of nonmetal elements.

After You ReadFOLDABLESReading & StudySkills

FOLDABLESReading &Study Skills

CHAPTER STUDY GUIDE 635

Study GuideChapter 2020

Study Tip

Vocabulary Wordsa. allotrope h. nonmetalb. diatomic molecule i. radioactive elementc. ductile j. semiconductord. malleable k. transition elemente. metal l. transuranium f. metallic bonding elementg. metalloid

Using VocabularyEach of the following sentences is false. Make

the sentence true by replacing the underlined word with a word from the list.

1. The radioactive elements are located to theleft of the stair-step line on the periodictable.

2. Different structural forms of the same element are called diatomic molecules.

3. Positively charged ions are surrounded byfreely moving electrons in a nonmetalelement.

4. An allotrope is a molecule comprised oftwo atoms.

5. The nonmetals are in Groups 3 through 12on the periodic table.

Outline the chapter to make sure that you’reunderstanding the key ideas. Writing down themain points of the chapter will help you toremember the important details and understandthe larger themes.

Complete the concept map using the following: Transition elements, hydrogen, Metals, Gas or brittle solid at room temperature, Inner transition metals, Metalloids, Noble gases.

Elements

Parts of Groups 13, 14,

and 15

Alkali metalsand alkalineearth metals

Nonmetals

areareare

include

includeinclude

Elements in green on thestairstep line

Malleable, ductile,and good conductors

Elements with properties similar to metals

and nonmetals

Halogensexcept

astatine

AssessmentChapter 2020

636 CHAPTER ASSESSMENT

Choose the word or phrase that best answersthe question.

1. When magnesium and fluorine react, whattype of bond is formed?A) metallic C) covalentB) ionic D) diatomic

2. What type of bond is found in a piece ofpure gold?A) metallic C) covalentB) ionic D) diatomic

3. Because electrons move freely in metals,which property describes metals?A) brittle C) dullB) hard D) conductors

4. Which set of elements makes up the mostreactive group of all metals?A) iron triad C) alkali metalsB) coinage metals D) alkaline earth metals

5. Which element is the most reactive of allnonmetals?A) fluorine C) hydrogenB) uranium D) oxygen

6. Which element is always found in naturecombined with other elements?A) copper C) magnesiumB) gold D) silver

7. Which elements are least reactive?A) metals C) noble gasesB) halogens D) actinides

8. What element is formed when neptuniumdisintegrates?A) ytterbium C) americiumB) promethium D) plutonium

9. Which element is an example of a radio-active element?A) astatine C) chlorineB) bromine D) fluorine

10. Which is the only group that is completelynonmetallic?A) 1 C) 17B) 2 D) 18

11. Why is mercury rarely used in thermome-ters that take body temperature?

12. The density of hydrogen is lower than airand can be used to fill balloons. Why ishelium used instead of hydrogen?

13. Copper is a good choice for use in electricalwiring. What type of elements would notwork well for this purpose? Why?

14. Why are various silver compounds used inphotography?

15. Like selenium, chromium is poisonous butis needed in trace amounts in your diet.Describe how you would apply this infor-mation in order to use vitamin and mineralpills safely.

16. Making and Using Tables Use the periodictable to classify each of the following as alanthanide or actinide: californium,europium, cerium, nobelium, terbium,and uranium.

17. Comparing and Contrasting Aluminum is close to carbon on the periodic table.Explain why aluminum is a metal and carbon is not.

18. Drawing Conclusions You are shown twosamples of phosphorus. One is white andburns if exposed to air. The other is red andburns if lit. Infer why the properties of twosamples of the same element differ.

CHAPTER ASSESSMENT 637

All of the elements that make up mat-ter can be divided into groups by lookingat their different characteristics. Examplesof two such groups of elements are listedin Tables A and B below.

Study the tables and answer the following questions.

1. The elements in Table A are differentfrom the elements in Table B becauseonly the elements in Table A _____ .A) are shiny and malleableB) are gases C) dissolve instantly in waterD) are yellow

2. Which of these belongs with Table A?F) nitrogen gasG) chlorine gasH) aluminum foilJ) water

3. The title of Table A is likely to be _____ .A) metalsB) nonmetalsC) metalloidsD) elements

4. Which of the following elements doesnot belong in Table B?F) oxygenG) fluorineH) sodiumJ) bromine

Test Practice

Iron

Silver

Copper

Table A

Helium

Carbon

Sulfur

Table B

AssessmentChapter 2020

19. Recognizing Cause and Effect Plants neednitrogen compounds. Nitrogen fixingchanges free nitrogen into nitrates. Light-ning and legumes are possible examples ofnitrogen fixing. What are the cause andeffect of nitrogen fixing in this example?

20. Concept Mapping Complete the conceptmap using the following: Na, Fe, Actinides,Hg, Ba, Alkali, and Inner transition.

21. Analyze the Data The model made in thetwo-page activity of this chapter helpsexplain the lubricating ability of graphite.Use that same model to explain how thegraphite in a pencil is able to leave a markon a piece of paper.

22. Investigate a Controversial Issue Researchthe pros and cons of using nuclear energyto produce electricity. Prepare a report thatincludes data as well as your informedopinion on the subject.

Go to the Glencoe Science Web site at science.glencoe.com or use the Glencoe Science CD-ROM for additionalchapter assessment.

TECHNOLOGY

K Na

Ba

Alkali

Fe Hg

Ag

Transition

Actinides Lanthanides

Inner transition

Metals


how are billiards bottles - irion-isd.org · you ride in. figure 1 the various properties of metals...

Documents