2Topic 10: Elements Basic Concepts Additional Concepts Topic 10 Table of ContentsTopic10Topic 10: ElementsBasic ConceptsAdditional Concepts
3Periodic Properties of the Elements Elements: Basic ConceptsTopic10Periodic Properties of the ElementsAn element’s chemical and physical properties are closely related to its position in the periodic table and that certain properties repeat periodically.Both position in the periodic table and the properties of the elements arise from the electron configurations of their atoms.
4Periodic Properties of the Elements Elements: Basic ConceptsTopic10Periodic Properties of the ElementsUnderstanding the relationship between electron configuration and position in the periodic table enables you to predict the properties of the elements and the outcome of many chemical reactions.
5Behavior of Main Group Elements Elements: Basic ConceptsTopic10Behavior of Main Group ElementsElements in the same group (vertical column) of the periodic table have the same number of valence electrons, and because of this, they have similar properties.But elements in a period (horizontal row) have properties different from one another.
6Behavior of Main Group Elements Elements: Basic ConceptsTopic10Behavior of Main Group ElementsThis is because the number of valence electrons increases from one to eight as you move from left to right in any row of the periodic table except the first.As a result, the character of the elements changes.
7Behavior of Main Group Elements Elements: Basic ConceptsTopic10Behavior of Main Group ElementsEach period begins with two or more metallic elements, which are followed by one or two metalloids.The metalloids are followed by nonmetallic elements, and every period ends with a noble gas.
8Trends in Metallic Properties Elements: Basic ConceptsTopic10Trends in Metallic Properties
9Patterns in Atomic Size Elements: Basic ConceptsTopic10Patterns in Atomic SizeRecall that the size of an atom increases in any group of elements as you go down the column because the valence electrons are found in energy levels farther and farther from the nucleus.But how does atomic radius change across a period from left to right?The lithium atom, with only three electrons, is actually larger than the fluorine atom, which has nine.
10Patterns in Atomic Size Elements: Basic ConceptsTopic10Patterns in Atomic SizeThere’s a simple explanation for the trend of decreasing atomic size across a period.Picture the valance electron on a lithium atom.The lithium nucleus has three protons, so there’s an attractive force of 3+ acting on the electron.
11Patterns in Atomic Size Elements: Basic ConceptsTopic10Patterns in Atomic SizeNow, think about the valence electrons in a beryllium atom.Here, there is an attractive force of 4+ from the four protons in the beryllium nucleus.
12Patterns in Atomic Size Elements: Basic ConceptsTopic10Patterns in Atomic SizeWith each increase in nuclear charge across the period, the outer electrons are attracted more strongly toward the nucleus, resulting in smaller size.
13Atomic Radii of Main Group Elements Elements: Basic ConceptsTopic10Atomic Radii of Main Group Elements
14Elements: Basic Concepts Topic10Ionic SizeAtomic size is an important factor in the chemical reactivity of an element.Ionic size is also important in determining how ions behave in solution and the structure of solid ionic compounds.
15Elements: Basic Concepts Topic10Ionic SizeWhen metallic atoms lose one or more electrons to become positive ions, they acquire the configuration of the noble gas in the preceding period.This means that the outermost electrons of the ion are in a lower energy level than the valence electrons of the neutral atom.
16Size of Atoms and Their Ions Elements: Basic ConceptsTopic10Size of Atoms and Their IonsThe electrons that are not lost by the atom experience a greater attraction to the nucleus and pull together in a tighter bundle with a smaller radius.The result is that all positive ions have smaller radii than their corresponding atoms.
17Size of Atoms and Their Ions Elements: Basic ConceptsTopic10Size of Atoms and Their IonsWhen an atom gains electrons to become a negative ion, the atom acquires the electron configuration of the noble gas at the end of its period.But the nuclear charge doesn’t increase with the number of electrons.
18Size of Atoms and Their Ions Elements: Basic ConceptsTopic10Size of Atoms and Their IonsIn the case of fluorine, a nuclear charge of 9+ must hold ten electrons in the F– ion.The result is that all the electrons are held less tightly, and the radius of the ion is larger than the neutral atom.
19Patterns in Ionic Radii― The Alkali Metals Elements: Basic ConceptsTopic10Patterns in Ionic Radii― The Alkali MetalsThe Group 1 elements—lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr)—are called the alkali metals. The alkali elements are soft, silvery-white metals and good conductors of heat and electricity.Click box to view movie clip.
20Patterns in Ionic Radii― The Alkali Metals Elements: Basic ConceptsTopic10Patterns in Ionic Radii― The Alkali MetalsTheir chemistry is relatively uncomplicated; they lose their s valence electron and form a 1+ ion with the stable electron configuration of the noble gas in the preceding period.
21Patterns in Ionic Radii― The Alkaline Earth Metals Elements: Basic ConceptsTopic10Patterns in Ionic Radii― The Alkaline Earth MetalsThe Group 2 elements—beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra)—are called the alkaline earth metals.
22Patterns in Ionic Radii― The Alkaline Earth Metals Elements: Basic ConceptsTopic10Patterns in Ionic Radii― The Alkaline Earth MetalsThe properties of Group 2 elements are similar to those of the Group 1 elements.Like the alkali metals, they are too reactive to be found as free elements in nature.They lose both of their s valence electrons and form 2+ ions with the stable electron configuration of the noble gas in the preceding period.
23Important Properties of Magnesium Elements: Basic ConceptsTopic10Important Properties of MagnesiumAlloys of magnesium are used where light weight and strength are important, as in this jet engine.Magnesium resists corrosion because it reacts with oxygen in the air to form a coating of magnesium oxide.The coating of MgO protects the metal underneath from further reaction with oxygen.
24Strontium Reveals Its Presence Elements: Basic ConceptsTopic10Strontium Reveals Its PresenceStrontium is a less well-known element of Group 2, but it’s important, nevertheless.Because of its chemical similarity to calcium, strontium can replace calcium in the hydroxyapatite of bones and form Sr5(PO4)3OH.
25Strontium Reveals Its Presence Elements: Basic ConceptsTopic10Strontium Reveals Its PresenceThis could be a problem only if the strontium atoms are the radioactive isotope strontium-90, which is hazardous if it is incorporated into a person’s bones.
26Only boron, the first element in Group 13, is a metalloid. Elements: Basic ConceptsTopic10Group 13 ElementsOnly boron, the first element in Group 13, is a metalloid.The other Group 13 elements—aluminum (Al), gallium (Ga), indium (In), and thallium (Tl)—are metals.
27Elements: Basic Concepts Topic10Group 13 ElementsNone of the metals are as active as the metals in Groups 1 and 2, but they’re good conductors of heat and electricity.
28The Uses of Group 13 Elements Elements: Basic ConceptsTopic10The Uses of Group 13 ElementsBoron is a metalloid found in boric acid (H3BO3) and borax (Na2B4O7•10H2O).Boric acid is one of the active ingredients in eyewash or contact lens-cleaning solution.Borax is the abrasive in some tough cleansing powders.It’s also used as a water softener and is an important component in some types of glass.
29Elements: Basic Concepts Topic10Group 14 ElementsThe Group 14 elements—carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb)—exhibit a variety of properties.
30Elements: Basic Concepts Topic10Group 14 ElementsCarbon is a nonmetal, silicon and germanium are metalloids, and tin and lead are metals.
31Nitrogen and phosphorus are nonmetals. Elements: Basic ConceptsTopic10Group 15 ElementsThe trend in metallic properties is obvious as you go from the top of Group 15 to the bottom—from nitrogen (N) to phosphorus (P) to arsenic (As) to antimony (Sb) and bismuth (Bi).Nitrogen and phosphorus are nonmetals.
32They form covalent bonds to complete their outer-level configuration. Elements: Basic ConceptsTopic10Group 15 ElementsThey form covalent bonds to complete their outer-level configuration.Arsenic and antimony are metalloids and either gain or share electrons to complete their octets.Bismuth is more metallic and often loses electrons.
33Their valence-electron configuration is s2p4. Elements: Basic ConceptsTopic10Group 16 ElementsThe Group 16 elements—oxygen (O), sulfur (S), selenium (Se), and tellurium (Te)—are nonmetals, and polonium (Po) is a metalloid.Their valence-electron configuration is s2p4.With rare exceptions, oxygen gains two electrons and forms the oxide ion (O2–) with the neon configuration.
34Elements: Basic Concepts Topic10Group 16 ElementsOxygen reacts with both metals and nonmetals and, among the nonmetals, is second only to fluorine in chemical reactivity.
35Elements: Basic Concepts Topic10Group 17 ElementsThe halogens—fluorine (F), chlorine (Cl), bromine (Br), idodine (I), and astatine (At)—are active nonmetals.Because of their chemical reactivity, they don’t exist as free elements in nature.
36Elements: Basic Concepts Topic10Group 17 ElementsTheir chemical behavior is characterized by a tendency to gain one electron to complete their s2p5 valence-electron configuration and form a 1– ion with a noble-gas configuration.
37Elements: Basic Concepts Topic10Group 18 ElementsHelium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn), the noble gases, were originally called the inert gases because chemists couldn’t get them to react.Access Code: EC787C089C
38Properties of the Transition Elements Elements: Basic ConceptsTopic10Properties of the Transition ElementsWith the exception of the Group 12 elements (zinc, cadmium, and mercury), the transition metals have higher melting points and boiling points than those of almost all of the main group elements.
39Properties of the Transition Elements Elements: Basic ConceptsTopic10Properties of the Transition ElementsMultiple oxidation states are characteristic of the transition elements.Many of the transition elements can have multiple oxidation numbers ranging from 2+ to 7+.
40Properties of the Transition Elements Elements: Basic ConceptsTopic10Properties of the Transition ElementsThese oxidation numbers are due to involvement of the d electrons in chemical bonding.
41Lanthanides and Actinides: The Inner Transition Elements Elements: Basic ConceptsTopic10Lanthanides and Actinides:The Inner Transition ElementsIn the lanthanides, electrons of highest energy are in the 4f sublevel.The lanthanides were once called rare earth elements because all of these elements occurred in Earth’scrust as earths, an older term for oxides, and seemed to be relatively rare.
42Lanthanides and Actinides: The Inner Transition Elements Elements: Basic ConceptsTopic10Lanthanides and Actinides:The Inner Transition ElementsThe highest-energy electrons in the actinides are in the 5f sublevel.
43Basic Assessment Questions Topic10Question 1Explain why elements within the same group of the periodic table are similar but not identical in properties, such as ionization energy.
44Basic Assessment Questions Topic10AnswerElements within the same group of the periodic table have the same number of valence electrons, but different numbers of nonvalence electrons.
45Basic Assessment Questions Topic10Question 2Compare the alkali and alkaline earth metals in terms of position in the periodic table, number of valence electrons, and overall properties.
46Basic Assessment Questions Topic10AnswerThe alkali metals have one valence electron and are in group 1A. The alkaline earth metals have two valence electrons and are in group 2A. Both types of metals are reactive, but the alkaline earth metals are less reactive. The alkali metals are softer.
47Basic Assessment Questions Topic10Question 3Compare the metallic character of the elements carbon, silicon, and lead. What do these elements have in common in terms of valance electrons and placement in the periodic table?
48Basic Assessment Questions Topic10AnswerCarbon is a nonmetal, silicon is a metalloid, and lead is a metal. All have four valence electrons and are located in group 4A.
50Reactivity of the Group 1A Element, Lithium Elements: Additional ConceptsTopic10Reactivity of the Group 1A Element, LithiumLithium is the most active metal in the second period because it can attain the noble-gas configuration of helium by losing a single electron.If lithium loses one electron from its 2s sublevel, its electron configuration changes from 1s22s1 to 1s2.
51Reactivity of the Group 1A Element, Lithium Elements: Additional ConceptsTopic10Reactivity of the Group 1A Element, LithiumThe resulting lithium ion has a 1+ charge and the same electron configuration as a helium atom.While this is not an octet, it is a noble-gas configuration.Elements tend to react in ways that allow them to achieve the configuration of the nearest noble gas.
52Reactivity of the Group 2A Element, Beryllium Elements: Additional ConceptsTopic10Reactivity of the Group 2A Element, BerylliumBeryllium, the next element in the second period, must lose a pair of 2s electrons to acquire the helium configuration.It’s harder to lose two electrons than it is to lose one, so beryllium is slightly less reactive than lithium.Nevertheless, beryllium does react by losing both of its 2s electrons and forming a 2+ ion with the helium electron configuration.
53Reactivity of the Group 3A Element, Boron Elements: Additional ConceptsTopic10Reactivity of the Group 3A Element, BoronIf this pattern continued, you would expect boron to lose three electrons to attain the helium configuration.Sometimes, boron does react by losing electrons, but often it reacts by sharing electrons.Boron is the only metalloid in the period.
54Reactivity of the Group 3A Element, Boron Elements: Additional ConceptsTopic10Reactivity of the Group 3A Element, BoronThat means boron sometimes behaves like a metal and loses electrons like its neighboring metals, lithium and beryllium.When it loses electrons, boron achieves the noble-gas configuration of helium.
55Reactivity of the Group 3A Element, Boron Elements: Additional ConceptsTopic10Reactivity of the Group 3A Element, BoronBut more often, boron acts like a nonmetal and shares electrons.Boron is unusual because it has only three electrons to share and cannot acquire an octet of electrons by just sharing.
56Reactivity of the Group 4A, 5A, 6A, and 7A Elements, C, N, O, and F Elements: Additional ConceptsTopic10Reactivity of the Group 4A, 5A, 6A, and 7A Elements, C, N, O, and FCarbon, nitrogen, oxygen, and fluorine are nonmetals.Carbon, with the configuration [He]2s22p2, and nitrogen, with the configuration [He]2s22p3, share electrons to attain the noble-gas configuration of neon, [He]2s22p6.
57Reactivity of the Group 4A, 5A, 6A, and 7A Elements, C, N, O, and F Elements: Additional ConceptsTopic10Reactivity of the Group 4A, 5A, 6A, and 7A Elements, C, N, O, and FOxygen, with the configuration [He]2s22p4, gains two electrons to form the oxide ion, O2–.Fluorine, with the configuration [He]2s22p5, gains one electron to become the fluoride ion, F–.
58Reactivity of the Group 1A Elements: The Alkali Metals Elements: Additional ConceptsTopic10Reactivity of the Group 1A Elements:The Alkali MetalsBecause of their chemical reactivity, the alkali metals don’t exist as free elements in nature.Sodium, for example, is found mostly combined with chlorine in sodium chloride.Click box to view movie clip.
59Reactivity of the Group 1A Elements: The Alkali Metals Elements: Additional ConceptsTopic10Reactivity of the Group 1A Elements:The Alkali MetalsMetallic sodium is obtained from NaCl through a process called electrolysis in which an electric current is passed through the molten salt.
60Spontaneous Reactivity Elements: Additional ConceptsTopic10Spontaneous ReactivitySodium and the other Group 1 elements are among the most active of all the metals.All Group 1 metals react vigorously with water.When they do, they replace hydrogen and form a hydroxide, as shown in the following equation.
61Alkali Metals Form Hydroxides Elements: Additional ConceptsTopic10Alkali Metals Form HydroxidesSo much heat is generated in the rapid reaction of potassium and water that the hydrogen gas produced in the reaction bursts into flames.Potassium hydroxide (KOH) formed in the reaction makes the solution alkaline. Hydroxides are important household and industrial chemicals.
62Household, Industrial, and Biological Uses Elements: Additional ConceptsTopic10Household, Industrial, and Biological UsesSodium hydroxide is used in the digestion of pulp in the process of making paper.It’s also used in making soap, in petroleum refining, in thereclaiming of rubber, and in the manufacture of rayon.
63Household, Industrial, and Biological Uses Elements: Additional ConceptsTopic10Household, Industrial, and Biological UsesIt is sodium hydroxide’s ability to convert fats to soap that makes it effective as a kitchen drain cleaner.Compounds of sodium and potassium are important to the human body because they supply the positive ions that play a key role in transmitting nerve impulses that control muscle functions.
64Household, Industrial, and Biological Uses Elements: Additional ConceptsTopic10Household, Industrial, and Biological UsesPotassium is also an essential nutrient for plants.It’s one of the three major components of fertilizers; the other two are also main group elements—nitrogen and phosphorus.
65Reactivity of the Group 2A Elements, the Alkaline Earth Metals Elements: Additional ConceptsTopic10Reactivity of the Group 2A Elements, the Alkaline Earth MetalsThe most reactive element in the alkaline earth group is the one with the largest atomic radius and, therefore, the least attraction for its two valence electrons.Knowing this, you can predict that radium, the largest atom in the group, is the most reactive.
66Reactivity of the Group 2A Elements, the Alkaline Earth Metals Elements: Additional ConceptsTopic10Reactivity of the Group 2A Elements, the Alkaline Earth MetalsThe trend to increasing reactivity with increasing size of atom for the alkaline earth metals is illustrated by the reaction of the elements with water.
67Reactions of Magnesium and Calcium Elements: Additional ConceptsTopic10Reactions of Magnesium and CalciumMagnesium oxide is also formed when magnesium is heated in air.It burns vigorously, producing a brilliant white light and magnesium oxide.In the process, magnesium loses two electrons to form the Mg2+ ion, and oxygen gains two electrons to form the O2– ion.
68Reactions of Magnesium and Calcium Elements: Additional ConceptsTopic10Reactions of Magnesium and CalciumTogether, they form the ionic compound MgO.The following equation shows what happens.
69Reactions of Strontium Elements: Additional ConceptsTopic10Reactions of StrontiumStrontium makes its presence known by the brilliant red color of a fireworks display.The red color also identifies strontium in laboratory flame tests.
70Reactivity of the Group 13 Elements: The Importance of Aluminum Elements: Additional ConceptsTopic10Reactivity of the Group 13 Elements: The Importance of AluminumBecause aluminum is neither as hard nor as strong as steel, it is often alloyed with other metals to make structural materials.Aluminum alloys are used in automobile engines, airplanes, and truck bodies where high strength and light weight are important.
71Elements: Additional Concepts Topic10Aluminum in Your HomeAt home, you may find bicycles, outdoor furniture, ladders, and pots and pans that are made of aluminum or an aluminum alloy.
72Aluminum as a Conductor Elements: Additional ConceptsTopic10Aluminum as a ConductorEven though aluminum doesn’t conduct electricity as well as copper, it costs less to use aluminum than copper for transmission of electricity.Aluminum cables are much lighter than copper cables, so fewer support towers are needed to hold the miles and miles of cable that span the country.
73Gallium’s Low Melting Point Elements: Additional ConceptsTopic10Gallium’s Low Melting PointGallium, indium, and thallium react much like aluminum.But gallium, shown here, has an unusually low melting point, 29.8°C.The heat of a hand is sufficient to liquefy the metal. For comparison, aluminum melts at 660ºC.
74Reactivity of the Group 14 Elements: Silicon Elements: Additional ConceptsTopic10Reactivity of the Group 14 Elements: SiliconSilicon, like boron, is a metalloid.It occurs in sand as silicon dioxide, SiO2—sometimes called silica.About 59 percent of Earth’s crust is made up of silica.In its elemental form, silicon is a hard, gray solid with a relatively high melting point, 1410ºC.
75Reactivity of the Group 14 Elements: Silicon Elements: Additional ConceptsTopic10Reactivity of the Group 14 Elements: SiliconSilicon is in window glass and in the chips that run computers.Compounds of silicon are found in lubricants, caulking, and sealants.
76Special Glasses from Silicon Elements: Additional ConceptsTopic10Special Glasses from SiliconSilicon is important in semiconductors.It’s also important in making alloys and in ceramics, glass, and cement.The glass-ceramic shown here doesn’t expand when heated so it won’t break when exposed to large temperature changes.
77The coating protects the steel from corrosion. Elements: Additional ConceptsTopic10“Tin” Cans and AlloysTin (Sn) is best known for its use as a protective coating for steel cans used for food storage.The coating protects the steel from corrosion.
78Tin is a soft metal that can be rolled into thin sheets of foil. Elements: Additional ConceptsTopic10“Tin” Cans and AlloysTin is also a principal component in the alloys bronze, solder, and pewter.Tin is a soft metal that can be rolled into thin sheets of foil.
79The Lead-Acid Storage Battery Elements: Additional ConceptsTopic10The Lead-Acid Storage BatteryLead (Pb) has been known and used since ancient times.It’s obtained from the ore galena (PbS).Lead is alloyed with tin in solder and cheaper grades of pewter.The most important use of lead is in the lead-acid storage batteries used in automobiles.
80Reactivity of the Group 15 Elements Elements: Additional ConceptsTopic10Reactivity of the Group 15 ElementsNitrogen, as the chemically unreactive molecule N2, makes up 78 percent by volume of Earth’s atmosphere.Plants and animals can’t use nitrogen in this form.Lichens, soil bacteria, and bacteria in the root nodules of beans, clover and other similar plants convert nitrogen to ammonia and nitrate compounds.
81Reactivity of the Group 15 Elements Elements: Additional ConceptsTopic10Reactivity of the Group 15 ElementsLightning also converts atmospheric nitrogen to nitrogen monoxide (NO).Plants use these simple nitrogen compounds to make proteins and other complex nitrogen compounds that become part of the food chain.
82Ammonia, the Essential Fertilizer Elements: Additional ConceptsTopic10Ammonia, the Essential FertilizerAmmonia is used as a liquid fertilizer applied directly to soil, or it can be converted to solid fertilizers such as ammonium nitrate, NH4NO3; ammonium sulfate, (NH4)2SO4; or ammonium hydrogen phosphate, (NH4)2HPO4.
83Two Allotropes of Phosphorus Elements: Additional ConceptsTopic10Two Allotropes of PhosphorusWhite and red phosphorus are two common allotropes of phosphorus.Notice that the white phosphorus is photographed under a liquid because this form of phosphorus, which has the formula P4 reacts spontaneously with oxygen in the air.
84Two Allotropes of Phosphorus Elements: Additional ConceptsTopic10Two Allotropes of PhosphorusRed phosphorus is used in making matches.
85Gallium Arsenide Semiconductors Elements: Additional ConceptsTopic10Gallium Arsenide SemiconductorsArsenic is a metalloid found widely distributed in Earth’s crust.An increasingly important use of the element is in the form of the binary compound gallium arsenide, GaAs.Because of its higher speed and performance, gallium arsenide is now replacing silicon in some of its semi-conductor applications in electronic circuitry.
86Antimony improves the hardness and corrosion resistance of the metal. Elements: Additional ConceptsTopic10AntimonyAntimony (Sb) is used primarily in alloys with other materials, particularly lead.Antimony improves the hardness and corrosion resistance of the metal.
87Reactivity of the Group 16 Elements Elements: Additional ConceptsTopic10Reactivity of the Group 16 ElementsLike oxygen, sulfur gains two electrons and forms the sulfide ion (S2–) when it reacts with metals or with hydrogen.But in its reactions with nonmetals, sulfur can have other oxidation numbers.Much of the sulfur produced in the United States is taken from deposits of elemental sulfur by the Frasch process of mining.
88Unstable Hydrogen Peroxide Elements: Additional ConceptsTopic10Unstable Hydrogen PeroxideIn your household chemical storehouse, you’ll find oxygen in solutions of hydrogen peroxide (H2O2), shown in a brown bottle.
89An Application of Selenium’s Photosensitivity Elements: Additional ConceptsTopic10An Application of Selenium’s PhotosensitivityThe chemistry of selenium and tellurium is similar to that of sulfur.Selenium has the property of increased electrical conductivity when exposed to light.This property has applications in security devices and mechanical opening and closing devices, where the interruption of a beam of light triggers an electrical response.
90Fluorides Prevent Tooth Decay Elements: Additional ConceptsTopic10Fluorides Prevent Tooth DecayMany towns and cities add fluorides to their water supply, and sodium fluoride (NaF) or tin(II) fluoride (SnF2) is often added to toothpastes to prevent tooth decay.
91Silver Bromide Coats Photographic Film Elements: Additional ConceptsTopic10Silver Bromide Coats Photographic FilmThe compound of the halogens are more important than the free elements.Compounds of chlorine with carbon, such as carbon tetrachloride and chloroform, are important solvents.Silver bromide (AgBr) is important in the light-sensitive coating on film.
92Reactivity of Group 18 Elements, Noble Gases Elements: Additional ConceptsTopic10Reactivity of Group 18 Elements, Noble GasesThe lack of reactivity of noble gases is understandable; all the noble gases have a full complement of valence electrons and of noble gasses, therefore, no tendency to gain or lose electrons.
93Reactivity of the Group 3-12 Elements, Transition Elements: Iron Elements: Additional ConceptsTopic10Reactivity of the Group 3-12 Elements, Transition Elements: IronBesides its importance as a structural metal, iron is an essential element in biological systems.It is the iron ion at the center of the heme molecule that binds oxygen.
94Elements: Additional Concepts Topic10ChromiumWhen chromium is alloyed with iron, tough, hard steels or steels that are corrosion-resistant are formed.Chromium is also alloyed with other transition metals to produce structural alloys for use in jet engines that must withstand high temperatures.A self-protective metal, chromium is often plated onto other materials to protect them from corrosion.
95Like chromium, zinc is a corrosion-resistant metal. Elements: Additional ConceptsTopic10ZincLike chromium, zinc is a corrosion-resistant metal.One of its principal uses is as a coating on iron and steel surfaces to prevent rusting.In the process called galvanizing, a surface coating of zinc is applied to iron by dipping the iron into molten zinc.
96Zinc is also important when alloyed with other metals. Elements: Additional ConceptsTopic10ZincZinc is also important when alloyed with other metals.The most important of these alloys is the combination of zinc with copper in brass.
97Reactivity of Lanthanides and Actinides: Cerium Elements: Additional ConceptsTopic10Reactivity of Lanthanides and Actinides: CeriumCerium is the principal metal in the alloy called misch metal.Misch metal is 50 percent cerium combined with lanthanum, neodymium, and a small amount of iron.
98Other lanthanides are used in the glass industry. Elements: Additional ConceptsTopic10Other LanthanidesOther lanthanides are used in the glass industry.Neodymium (Nd) is used not only to decolorize glass but to add color to glass.When added to the glass used for welders’ goggles, neodymium and praseodymium (Pr) absorb the eye-damaging radiation from welding.
99Radioactivity and the Actinides Elements: Additional ConceptsTopic10Radioactivity and the ActinidesUranium (U) is a naturally occurring, radioactive element used as a source of nuclear fuel and other radioactive elements.Plutonium (Pu) is one of the elements obtained from the use of uranium as a nuclear fuel.
100Radioactivity and the Actinides Elements: Additional ConceptsTopic10Radioactivity and the ActinidesSome actinides have medical applications: for example, radioactive californium-252 (Cf) is used in cancer therapy.Better results in killing cancer cells have been achieved using this isotope of californium than by sing the more traditional X-ray radiation.
101Additional Assessment Questions Topic10Question 1Name the elements in the following pair. Compare them in terms of group number, number of valence electrons, and metallic character.As and Bi
103Question 2 State a use for each element. A. Se and Cl B. I and H Additional Assessment QuestionsTopic10Question 2State a use for each element.A. Se and ClB. I and HC. S and F
104Answers A. Se: used in solar panels and photcopiers Additional Assessment QuestionsTopic10AnswersA. Se: used in solar panels and photcopiersCl: used as a bleach and disinfectantand to make certain plasticsB. I: silver compound used to coatphotographic filmHe: used in balloons and by diversC. S: used to make sulfuric acidF: used in toothpaste to protect tooth enamel
105Additional Assessment Questions Topic10Question 3An element is metallic and radioactive. It has six valence electrons. Identify the element’s group number and name the element.
107Additional Assessment Questions Topic10Question 4Compare the period-2 elements that are in groups 5A, 6A, 7A, and 8A in terms of number of valence electrons and reactivity.
108Additional Assessment Questions Topic10AnswersNitrogen (group 5A) has five valence electrons and is relatively unreactive.Oxygen (group 6A) has six valence electrons and is reactive.Fluorine (group 7A) has seven valence electrons and is extremely reactive.Neon (group 8A) has eight valence electrons and is extremely unreactive.
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