11

Periodic TablePeriodic Table

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Periodic Table DevelopmentPeriodic Table DevelopmentSeveral Early Schemes to Organize ElementsSeveral Early Schemes to Organize Elements

• Dobereiner-Early 1800’sDobereiner-Early 1800’s– Attempted to classify elements in triadsAttempted to classify elements in triads

• Newlands-1865Newlands-1865– Pattern of octavesPattern of octaves– Similar to periodic law of todaySimilar to periodic law of today

• Mendeleev & Meyer (1869)Mendeleev & Meyer (1869)– Organized elements by atomic massOrganized elements by atomic mass

• Moseley (1913)Moseley (1913)– Post-doctoral student working in Post-doctoral student working in

Rutherford’s labRutherford’s lab– Organized elements by atomic number Organized elements by atomic number

at age 26at age 26– Tragically killed in WW ITragically killed in WW I

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Abbreviated Electron Configurations

Where are Groups andPeriods?

3B 4B 5B 6B 7B 8B 1B 2B

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Partial electron configurations for the elements Partial electron configurations for the elements potassium through krypton.potassium through krypton.

Periodic LawWhen elements are arranged in order of increasing

atomic number, their physical and chemical properties exhibit a repeating (periodic) pattern

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Abbreviated Electron ConfigurationAbbreviated Electron Configuration

NeonNeon 1s1s222s2s222p2p66

Magnesium Magnesium 1s1s222s2s222p2p663 s3 s22

OrOr

[Ne][Ne] 3 s3 s22

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Periodic Table FamiliesPeriodic Table Families

Some groups (columns) are given family namesSome groups (columns) are given family names• Alkali MetalsAlkali Metals 1A1A• Alkaline Earth MetalsAlkaline Earth Metals 2A2A• Transition MetalsTransition Metals 1B-8B1B-8B• Inner Transition MetalsInner Transition Metals Lanthanides Lanthanides

and Actinidesand Actinides• HalogensHalogens 7A7A• Noble GasesNoble Gases 8A8A

Rows are called periodsRows are called periods

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Classification of elements as metals, nonmetals, and metalloids Classification of elements as metals, nonmetals, and metalloids (a.k.a. semimetals)(a.k.a. semimetals)

Metalloids are also called “Semimetals”

Valence Electrons

• Chemical compounds form because electrons are lost, gained, or shared between atoms.

• The electrons that interact in this manner are those in the highest energy levels.

• The electrons available to be lost, gained, or shared in the formation of chemical compounds are referred to as valence electrons.

• Valence electrons are often located in incompletely filled main-energy levels.

• example: the electron lost from the 3s sublevel of Na to form Na+ is a valence electron.

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Valence Electron: outermost electrons that enter into chemical bonds

For Group AGroup # = Valence #

3B 4B 5B 6B 7B 8B 1B 2B

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Octet RuleOctet Rule

• Atoms tend to gain, lose, or share Atoms tend to gain, lose, or share electrons in order to acquire a full set of electrons in order to acquire a full set of valence electronsvalence electrons

• A very important ruleA very important rule

• An Octet consist of eight electronsAn Octet consist of eight electrons– This refers to the outermost eight electronsThis refers to the outermost eight electrons

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Orbitals being filled for elements in Orbitals being filled for elements in various parts of the periodic table.various parts of the periodic table.

1212

Periodic Table BlocksPeriodic Table Blocks

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Complete Periodic TableComplete Periodic Table

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Important Trends in Periodic TableImportant Trends in Periodic Table• Atomic RadiusAtomic Radius

– Radius of the atomRadius of the atom

• Ionic SizeIonic Size– Radius of an ion of an element Radius of an ion of an element

• Ionization EnergyIonization Energy– Energy required to remove first electron Energy required to remove first electron

from an atom of an elementfrom an atom of an element

• Successive Ionization EnergySuccessive Ionization Energy– Energy required to remove next Energy required to remove next

electron from an atomelectron from an atom

• Electron AffinityElectron Affinity– Energy change that occurs when an Energy change that occurs when an

atom gains an electronatom gains an electron

• ElectronegativityElectronegativity– Ability of an atom to attract electrons in Ability of an atom to attract electrons in

a chemical bonda chemical bond

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Relative atomic sizes for selected atoms.Relative atomic sizes for selected atoms.

What are trendsin atomic size of ions?

1616

Relative sizes of some ions and their parent atoms.Relative sizes of some ions and their parent atoms.

1717

First Ionization EnergiesFirst Ionization Energies

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• Electron Affinity is Electron Affinity is the energy change the energy change that occurs when an that occurs when an electron is acquired electron is acquired by a neutral atomby a neutral atom

• Most atoms release Most atoms release energy when they energy when they acquire an electronacquire an electron

• The “-” sign means The “-” sign means the atom is giving off the atom is giving off energyenergy

Electron Affinity kJ/mol

1919

Electronegativity values for selected Electronegativity values for selected elements.elements.

2020

3B 4B 5B 6B 7B 8B 1B 2B

Periodic TrendsPeriodic TrendsPeriodic TrendsPeriodic TrendsAtomic radius decreasesAtomic radius decreases

Ionization energy increasesIonization energy increasesElectronegativity increasesElectronegativity increases

Atomic radius decreasesAtomic radius decreasesIonization energy increasesIonization energy increasesElectronegativity increasesElectronegativity increases

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Reactive Metals: s-block ElementsReactive Metals: s-block Elements

• Includes alkali and alkaline earth metalsIncludes alkali and alkaline earth metals

• Highly reactive-seek to lose electronsHighly reactive-seek to lose electrons

• Malleable, ductile, good conductorsMalleable, ductile, good conductors

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Alkali metals Group 1AAlkali metals Group 1A• Soft, cuts with a knifeSoft, cuts with a knife

• Tarnish rapidlyTarnish rapidly

• React with waterReact with water

• Similar behavior of all elements in familySimilar behavior of all elements in family

• Stored in oilStored in oil

• Low ionization energy: sLow ionization energy: s11 configuration configuration

• Low density and melting points—see fig. 6.3Low density and melting points—see fig. 6.3

• React in 1:1 ratio with halogensReact in 1:1 ratio with halogens

• Sodium and potassium are most abundantSodium and potassium are most abundant

• Never found free and uncombinedNever found free and uncombined

• Sodium used in large quantity commerciallySodium used in large quantity commercially– Several useful compounds: NaOH, NaClO, NaHCOSeveral useful compounds: NaOH, NaClO, NaHCO33, NaCO, NaCO33

• Lithium used in medicines LiLithium used in medicines Li22COCO33

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Alkaline Earth Metals Group 2AAlkaline Earth Metals Group 2A• Name dates to middle agesName dates to middle ages• Similar behavior to alkali metal oxides (hence name)Similar behavior to alkali metal oxides (hence name)• Similarities between family members but not so striking as 1ASimilarities between family members but not so striking as 1A• Higher densities and melting points—see fig 6-3Higher densities and melting points—see fig 6-3• Double the ionization energy as 1ADouble the ionization energy as 1A• Form oxide surface coatingForm oxide surface coating• Form compounds with halogens and other negative ions groupsForm compounds with halogens and other negative ions groups• Not found in elemental state due to reactivityNot found in elemental state due to reactivity• Only magnesium produced in large quantities from seawaterOnly magnesium produced in large quantities from seawater

– Produces excellent alloys with aluminumProduces excellent alloys with aluminum– In pure state—reacts with steamIn pure state—reacts with steam

• Calcium and heavier react with cold waterCalcium and heavier react with cold water• Beryllium is a strong metal with ¼ the weight of ironBeryllium is a strong metal with ¼ the weight of iron

– Makes excellent alloysMakes excellent alloys• Many important compounds of alkaline earth metalsMany important compounds of alkaline earth metals

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Transition Metals—d block ElementsTransition Metals—d block Elements

• Many excellent structural metalsMany excellent structural metals

• Important to living organismsImportant to living organisms

• Vary in abundanceVary in abundance

• High density ~20g/cmHigh density ~20g/cm33; Tungsten Melting Point ; Tungsten Melting Point 3410 3410 CC

• ChromiumChromium– Found in Russia, Philippines and AfricaFound in Russia, Philippines and Africa– Used in chromeUsed in chrome– Corrosion resistant (reaction between water, oxygen and Corrosion resistant (reaction between water, oxygen and

acid)acid)– Excellent alloysExcellent alloys– Reason for color of many compounds—often used in Reason for color of many compounds—often used in

pigmentspigments

2525

Transition Metals—d block ElementsTransition Metals—d block Elements

• IronIron– Commonly available strong, durable materialCommonly available strong, durable material– Occurs in magnetite, hematite, siderite, pyriteOccurs in magnetite, hematite, siderite, pyrite– Refined in blast furnaceRefined in blast furnace

– Corrodes readily to form iron oxide FeCorrodes readily to form iron oxide Fe22OO33 (rust) (rust)

– Important dietary elementImportant dietary element

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• Coin Metals: gold, silver and copperCoin Metals: gold, silver and copper– Copper used since about 5000 BCCopper used since about 5000 BC

• Combined with tin to from harder bronze alloyCombined with tin to from harder bronze alloy

– Silver and gold in use as least as long as Silver and gold in use as least as long as coppercopper

– Resist corrosionResist corrosion– Known for beautyKnown for beauty– AvailabilityAvailability

• CuCu #25#25

• AgAg #64#64

• AuAu #71#71

Transition Metals—d block ElementsTransition Metals—d block Elements

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Transition Metals—d block ElementsTransition Metals—d block Elements• CopperCopper

– Soft metal with reddish colorSoft metal with reddish color– Alloyed with zinc to make brassAlloyed with zinc to make brass– Excellent electrical conductor, only silver is betterExcellent electrical conductor, only silver is better– Reacts with O and CO to form green patinaReacts with O and CO to form green patina

• As seen on the Statue of LibertyAs seen on the Statue of Liberty– Copper compounds have green or blue colorCopper compounds have green or blue color

• Provide blues in fireworksProvide blues in fireworks

• SilverSilver– Lustrous white metalLustrous white metal– Soft—alloyed with other metals; Sterling contains 7.5% CuSoft—alloyed with other metals; Sterling contains 7.5% Cu– Used in photography, coinage, jewelry, silverware, Used in photography, coinage, jewelry, silverware,

electronicselectronics– Tarnishes with sulfide ion to form AgTarnishes with sulfide ion to form Ag22SS

• GoldGold– Dense, soft metal with yellow lusterDense, soft metal with yellow luster– Alloyed for durability—18karat gold is 75% goldAlloyed for durability—18karat gold is 75% gold

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Inner Transition Metals: f-block ElementsInner Transition Metals: f-block Elements

• Lanthanides: 4f seriesLanthanides: 4f series– Very similar to one anotherVery similar to one another– Readily lose 3 electronsReadily lose 3 electrons– Soft silvery metalsSoft silvery metals– Less reactive than alkaline earth metals, but still too Less reactive than alkaline earth metals, but still too

reactive for structural usereactive for structural use– Tarnish and air and react slowly with waterTarnish and air and react slowly with water– Used in making steel alloysUsed in making steel alloys

• Actinides: 5fActinides: 5f– Radioactive elementsRadioactive elements– Thorium and uranium are found in nature more readily Thorium and uranium are found in nature more readily

than othersthan others

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Metals, Metalloids, and Nonmetals: p-Block Metals, Metalloids, and Nonmetals: p-Block ElementsElements

• Boron Group 3ABoron Group 3A– Boron is a semimetalBoron is a semimetal– Aluminum, Gallium, Indium, and Thallium Aluminum, Gallium, Indium, and Thallium

are metalsare metals– Form 3+ ionsForm 3+ ions– Aluminum is most important—extracted Aluminum is most important—extracted

from bauxite Alfrom bauxite Al22OO33

•Charles Hall—a college student—developed Charles Hall—a college student—developed refining processrefining process

•Al has low density but forms strong alloysAl has low density but forms strong alloys

•Resistant to corrosion—forms oxideResistant to corrosion—forms oxide

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Metals, Metalloids, and Nonmetals: p-Block Metals, Metalloids, and Nonmetals: p-Block ElementsElements

• Carbon Group 4ACarbon Group 4A– Carbon is non metalCarbon is non metal– Si and Ge are semimetalsSi and Ge are semimetals– Sn and Pb are metalsSn and Pb are metals

• CarbonCarbon– Very commonVery common– Hydrocarbons are major components of fuelsHydrocarbons are major components of fuels

• Also used in medicines and plasticsAlso used in medicines and plastics• Combustion produces carbon monoxide (CO) poisonous deadly gasCombustion produces carbon monoxide (CO) poisonous deadly gas

– CO reduced if oxygen is plentifulCO reduced if oxygen is plentiful

• COCO22 is non-toxic fizz in soda—dry ice below -78.5 is non-toxic fizz in soda—dry ice below -78.5CC

• SiliconSilicon– Highly abundant—SiOHighly abundant—SiO22 is sand is sand– Blended with CaO and NaBlended with CaO and Na22O to make glass; BO to make glass; B22OO33 makes pyrex makes pyrex– Metal oxides and cobalt added for colorMetal oxides and cobalt added for color

• Germanium, Tin and LeadGermanium, Tin and Lead– Ge used to make computer chipsGe used to make computer chips– Pb used by Romans to make water pipesPb used by Romans to make water pipes– Sn used to coat steel cans Sn used to coat steel cans

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Nitrogen Group 5ANitrogen Group 5A

• Nitrogen and Phosphorous are most commercially Nitrogen and Phosphorous are most commercially importantimportant

• NitrogenNitrogen– 80% of Earth’s atmosphere80% of Earth’s atmosphere– Colorless, odorlessColorless, odorless– Molecules have low reactivity—can’t be used by most Molecules have low reactivity—can’t be used by most

organisms directlyorganisms directly– Important fertilizer componentImportant fertilizer component– Combined with H to produce ammonia NHCombined with H to produce ammonia NH33

• 15,000,000,000 kg manufactured annually15,000,000,000 kg manufactured annually

• PhosphorousPhosphorous– Abundant in Earth’s crustAbundant in Earth’s crust– Found in living organisms: calcium hydroxyapatite CaFound in living organisms: calcium hydroxyapatite Ca55(PO(PO44))33OHOH– Phosphoric acid HPhosphoric acid H33POPO4 4 used in fertilizer, soda and detergentused in fertilizer, soda and detergent

• 10,000,000,000 kg manufacture in US annually10,000,000,000 kg manufacture in US annually

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Oxygen Group 6AOxygen Group 6A

• Oxygen and sulfur are most commonOxygen and sulfur are most common– 23% mass of air; 89% mass of water; 46% of crustal rock23% mass of air; 89% mass of water; 46% of crustal rock– Oxygen in molecular state exist as OOxygen in molecular state exist as O2 2 & O& O3 3 (ozone)(ozone)– Ozone formed in the presence of electricityOzone formed in the presence of electricity– Colorless, and tasteless; Ozone has strong odorColorless, and tasteless; Ozone has strong odor– Required for respiration and burningRequired for respiration and burning– Ozone attacks tissue and structural materialsOzone attacks tissue and structural materials

• Screens out UV radiationScreens out UV radiation

• SulfurSulfur– Solid yellow powder known as brimstone in ancient timesSolid yellow powder known as brimstone in ancient times– Sulfur containing compound added to natural gas to cause Sulfur containing compound added to natural gas to cause

odorodor– Used to produce HUsed to produce H22SOSO44

• 40,000,000,000 kg of sulfuric acid produced annually in US40,000,000,000 kg of sulfuric acid produced annually in US• Used in lubricants, paints, plastics, insecticides, explosives . . .Used in lubricants, paints, plastics, insecticides, explosives . . .

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Halogens 7AHalogens 7A• NonmetalsNonmetals

• Highly Reactive—React with metals to form salts—also react Highly Reactive—React with metals to form salts—also react with nonmetalswith nonmetals

• Ions are called halidesIons are called halides

• Exist in molecules diatomic form: FExist in molecules diatomic form: F22, Cl, Cl22, Br, Br22

• Do not exist in element state due to high reactivityDo not exist in element state due to high reactivity

• Reactivity decreases moving down the groupReactivity decreases moving down the group– Fluorine has highest electronegativityFluorine has highest electronegativity

• FluorineFluorine– Abundant in earth crust—never found uncombinedAbundant in earth crust—never found uncombined– Combined with C (fluorocarbons) and Cl (CFC’s)Combined with C (fluorocarbons) and Cl (CFC’s)

• Used to make teflon, lubricants, refrigerantsUsed to make teflon, lubricants, refrigerants

• ChlorineChlorine– Recovered from NaClRecovered from NaCl– Used as disinfectant, in bleach, and PVC plasticUsed as disinfectant, in bleach, and PVC plastic

• Bromine and IodineBromine and Iodine– Less abundant than C and FLess abundant than C and F– Used in fire retardants, pesticides, film, antisepticUsed in fire retardants, pesticides, film, antiseptic

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Noble Gases 8ANoble Gases 8A

• Lack reactivityLack reactivity

• Remain apart from other elementRemain apart from other element– Characteristic of nobility—hence nameCharacteristic of nobility—hence name

• Argon most abundant—1% of earth’s atmosphereArgon most abundant—1% of earth’s atmosphere

• Helium present in U ore and natural gas wellsHelium present in U ore and natural gas wells

• Larger Noble gases can be forced into reactionLarger Noble gases can be forced into reaction

• Helium is most commercially importantHelium is most commercially important– Lowest boiling point: -269Lowest boiling point: -269CC– Used as super cold refrigerantUsed as super cold refrigerant

• Neon gas produces red glow when voltage Neon gas produces red glow when voltage applied to itapplied to it

3535

HydrogenHydrogen

• Placed in group 1A, but it is not a metalPlaced in group 1A, but it is not a metal

• Greater ionization energy than lithiumGreater ionization energy than lithium– Why?Why?

• Colorless, odorlessColorless, odorless

• Exists in the form of HExists in the form of H22

• Found in many organic compounds and atmosphereFound in many organic compounds and atmosphere

• Major use: manufacturing of ammonia NHMajor use: manufacturing of ammonia NH33 used in used in fertilizer and cleanersfertilizer and cleaners

• Also used to make Methanol CHAlso used to make Methanol CH33OH, a gasoline OH, a gasoline substitutesubstitute

• Explosive!Explosive!