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Chapter8.PeriodicPropertiesoftheElements
StudentObjectives
8.1
NerveSignalTransmission
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8.2
Knowthattheionsofsodiumandpotassium,twoGroup1Aelements,playmajorrolesinnerve‐
signaltransmission.
Knowthatthesodium‐potassiumpumpsincellmembranescandistinguishbetweenNa+andK+
becauseofeachion’sradius,oneofthemostprevalentperiodictrends.
TheDevelopmentofthePeriodicTable
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8.3
Knowthattherapiddiscoveryofnewelementsinthe19thcenturyresultedinseveralscientists’
effortstocategorizeallknownelements.
KnowthatMendeleevorganizedthemodernformoftheperiodictableinordertogrouptogether
elementswithsimilarcharacteristics.
Knowandunderstandthattheperiodiclawsummarizesthebehavioroftheelements—arranging
thembyatomicnumberresultsinstrongcorrelationwithelementalproperties.
ElectronConfigurations:HowElectronsOccupyOrbitals
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8.4
Knowandunderstandthatanelectronconfigurationshowsthenumberofelectronsthatoccupy
particularorbitalsinatomsandisthebasisforchemicalreactivity.
Knowthatthespinquantumnumber,m s ,canhavevaluesof+1/2and1/2.
KnowthePauliexclusionprinciple:Notwoelectronsinanatomcanhavethesamefourquantum
numbers.Consequently,amaximumoftwoelectronscanoccupyagivenorbital,andiftwoelectrons
occupythesameorbital,theyhaveoppositespins.
Understandthatthesublevelswithinagivenprincipalenergylevelare,fromlowestenergyto
highest,s<p<d<f.
Understandthegeneralprinciplesofelectronshieldingandorbitalpenetration.
Writeelectronconfigurations.
ElectronConfigurations,ValenceElectrons,andthePeriodicTable
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8.5
Definevalenceandcoreelectrons.
Knowthes,p,d,andfblocksoftheperiodictable.
Usetheperiodictabletopredictelectronconfigurations.
TheExplanatoryPoweroftheQuantum‐MechanicalModel

8.6
Understandthatmanyofthechemicalpropertiesofelementsareduetothenumberofvalence
electronsandthatelementsinthesamegrouphavethesamenumberofvalenceelectrons.
PeriodicTrendsintheSizeofAtomsandEffectiveNuclearCharge
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KnowthedefinitionsanddifferencesamongvanderWaals,covalent,andatomicradii.
Knowandpredicttrendsinatomicradiusdownagroup(largerradius)andtotherightacrossa
period(smallerradius).
Usetheideasofscreeningandeffectivenuclearchargetoexplainthetrendsforatomicradius.
Knowthattheradiioftransitionelementsremainapproximatelyconstantacrosseachperiod.
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Chapter8.PeriodicPropertiesoftheElements
8.7
Ions:ElectronConfigurations,MagneticProperties,IonicRadii,andIonizationEnergy
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8.8
Knowhowtowriteelectronconfigurationsforions.Foranions,extraelectronsaresimplyfilledin.
Forcations,electronsareremovedfromthehighestsublevelofthehighestprincipalenergylevel.
Identifyanddistinguishbetweenparamagneticanddiamagneticatoms/ions.
Knowtherelationshipbetweentheradiusofaneutralatomanditsions:cationsaresmallerwhile
anionsarelargerthanthecorrespondingneutralatom.
Knowandpredicttrendsinfirstionizationenergydownagroup(smallerionizationenergy)andto
therightacrossaperiod(largerionizationenergy).
Usetheideasofscreeningandeffectivenuclearchargetoexplainthetrendsforionizationenergy.
Understandtrendsinsecondandsuccessiveionizationenergieswithrespecttothenoble‐gascore.
ElectronAffinitiesandMetallicCharacter
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8.9
Defineandunderstandthebasictrendforelectronaffinity:Itgenerallygetslessexothermicdowna
groupandmoreexothermictotherightacrossaperiod.
Knowtheperiodictrendsinmetalliccharacter:Itincreasesdownagroupanddecreasestotheright
acrossaperiod.
SomeExamplesofPeriodicChemicalBehavior:TheAlkaliMetals,theHalogens,andthe
NobleGases

Knowthenames,periodictrends,andrepresentativechemicalreactionsoftheelementsofafew
groups:Group1A(alkalimetals),Group2A(alkalineearthmetals),Group7A(halogens),andGroup
8A(noblegases).
SectionSummaries
LectureOutline
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Terms,Concepts,Relationships,Skills
Figures,Tables,andSolvedExamples
TeachingTips


SuggestionsandExamples
MisconceptionsandPitfalls
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Copyright © 2014 by Pearson Education, Inc.
Chapter8.PeriodicPropertiesoftheElements
LectureOutline
Terms,Concepts,Relationships,Skills 8.1 NerveSignalTransmission
 Elementsinagroup
o
Figures,Tables,andSolvedExamples

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Na+andK+rolesinnerve
transmission
 Periodicproperty:radius
8.2TheDevelopmentofthePeriodicTable
 Historyofelementdiscoveryand
developmentoftheperiodictable
o Dobereiner,Mendeleev,Meyer,
Moseley
 Periodiclaw
o atomicmass,atomicnumber
8.3ElectronConfigurations:HowElectronsOccupy
Orbitals
 Electronconfiguration
o groundstateorbitalsandelectron
count
 Electronspin
o spinquantumnumber
o Pauliexclusionprinciple
o consequencesofPauliprinciple
 Energysplittingformultielectronatoms
o byprincipalenergylevel
 shielding
o bysublevels
 penetration
 Writingelectronconfigurations
o minimizeenergy
o twoelectronsperorbital
 Drawingorbitaldiagrams
o Hund’srule:electronsfirstoccupy
degenerateorbitalssinglywithpaired
spins
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Introfigure:cellmembraneandfluxofNa+,
K+ions
unnumberedfigure:Group1A
unnumberedfigure:RadiiofNa+andK+
unnumberedfigure:portraitofDmitri
Mendeleev
Figure8.1Eka‐aluminumandEka‐silicon
unnumberedfigure:orbitaldiagramforH
unnumberedfigure:chartoffourquantum
numbersforelectronsinHe
Equation8.1Coulomb’sLaw
Figure8.2ShieldingandPenetration
Figure8.3RadialDistributionFunctionsfor
the1s,2s,and2pOrbitals
Figure8.4RadialDistributionFunctionsfor
the3s,3p,and3dOrbitals
Figure8.5GeneralEnergyOrderingof
OrbitalsforMultielectronAtoms
unnumberedfigure:orbitaldiagramsoffirst
tenelements
Example8.1ElectronConfigurations
Example8.2WritingOrbitalDiagrams
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Chapter8.PeriodicPropertiesoftheElements
TeachingTips
SuggestionsandExamples
8.1NerveSignalTransmission
 Thebodyrequireslargequantitiesofsodiumand
potassiumforvariouspurposes,especiallythesodium‐
potassiumpumpthatfacilitatesnerve‐signal
transmission.Emphasizethesizesofthesetwoions
andthemembraneproteinsthatregulatetheirpassage
intoandoutofcells.
8.2TheDevelopmentofthePeriodicTable
 Askthestudentstoarrangetheelementsforthefirst
twoperiodsbyatomicmassinsteadofatomicnumber.
PointoutwheretheproblemsariseandwhyMendeleev
wassosuccessfulwithhisapproach.
 Findsomealternativeperiodictablestoshowinclass:
Monroe,C.J.;Turner,W.D.;J.Chem.Educ.1926,3,1058.
Emerson,EdgarI.;J.Chem.Educ.1944,21,111.
Sanderson,R.T.;J.Chem.Educ.1964,41,187.
8.3ElectronConfigurations:HowElectronsOccupyOrbitals
 Studentsneedhelpunderstandingthereasonsbehind
theorderoforbitals,especiallyforthoselike4sand5s
thatappeartobeoutoforder.Manywillpreferto
memorizealistinstead.
 ConceptualConnection8.1Coulomb’sLaw
 ConceptualConnection8.2PenetrationandShielding
 Forperiods5andhigher,studentsoftenforgetabout
theforbitalsinwritingconfigurations.
 ConceptualConnection8.3ElectronConfigurationsand
QuantumNumbers
MisconceptionsandPitfalls

Essentialmineralslikesodiumand
potassiumarepresentasionsand
notastheneutralformofthe
element,particularlysincethese
mineralsexistinanaqueous
environmentinthebody.

Theperiodiclawpredictsand
summarizeswhycertainelements
havesimilarproperties.The
quantumtheoryexplainsthebasis
ofthelaw.

Theorderofaddingelectrons(s,p,
d,f)topredicttheelectron
configurationofneutralatomsis
relativelysimplewithafew
exceptions.
Eachoftheperiodsdoesnothave
thesametotalnumberof
electrons.

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Chapter8.PeriodicPropertiesoftheElements
LectureOutline
Terms,Concepts,Relationships,Skills 8.4ElectronConfigurations,ValenceElectrons,and
thePeriodicTable
 Electronconfigurations
o coreelectrons
o valenceelectrons
 outermostprincipalenergy
level
 samevalenceelectroncount
forelementsinagroup
 Periodictable
o orbitalblocksfors,p,d,f
o electronconfigurationbypositionin
periodictable
o exceptionsfortransitionelements
8.5TheExplanatoryPoweroftheQuantum‐
MechanicalModel
 Periodicity
o elementsinsamegrouphavesimilar
properties
o elementsinsamegrouphavesame
valenceelectroncount
 Periodictableandionswithpredictable
charge
o explanationofconceptfromSection
2.7
8.6PeriodicTrendsintheSizeofAtomsandEffective
NuclearCharge
 radiusdefinitions
o vanderWaals
o covalent
o nonbonding
 radiustrend
o decreasestotherightacrossa
period
o increasesdownagroup
 effectivenuclearcharge
 differenceintrendsformain‐groupvs.
transitionelements
FiguresandSolvedProblems
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Figure8.6OuterElectronConfigurationsof
theFirst18ElementsinthePeriodicTable
Example8.3ValenceElectronsandCore
Electrons
Figure8.7Thes,p,d,andfBlocksofthe
PeriodicTable
unnumberedfigure:electronconfigurationof
Cl
Example8.4WritingElectronConfigurations
fromthePeriodicTable
unnumberedfigure:electronconfigurations
offirstandsecondrowtransitionmetals
unnumberedfigure:electronconfigurations
ofelementsinGroup8A
unnumberedfigure:electronconfigurations
ofelementsinGroups1Aand2A
unnumberedfigure:electronconfigurations
ofelementsinGroup7A
Figure8.8ElementsthatFormIonswith
PredictableCharges
unnumberedfigure:vanderWaalsradiusof
Kr
unnumberedfigure:covalentradiusofBr
Figure8.9AtomicRadiusversusAtomic
Number
Figure8.10TrendsinAtomicRadius
Figure8.11ScreeningandEffectiveNuclear
Charge
Example8.5AtomicSize
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Chapter8.PeriodicPropertiesoftheElements
TeachingTips
SuggestionsandExamples
8.4ElectronConfigurations,ValenceElectrons,andthePeriodic
Table
 Thedistinctionbetweencoreandvalenceelectronsis
animportantconceptthatexplainsperiodicityand
representthebasisforbondingandstructure.
 Theorganizationoftheperiodictablebyorbitalblocks
(Figure8.7)isgraphicalandsimplifieswritingelectron
configurationsbasedonpositionintheperiodictable.
8.5TheExplanatoryPoweroftheQuantum‐MechanicalModel
 Valenceelectronsdeterminechemicalpropertiesand
theformationofcommonions.Groups1Aand2Aform
cationsasdothetransitionelements,buttheformer
arerestrictedtoasinglecharacteristiccharge
especiallybecauseoftheeaseofattaininganoble‐gas
configuration.
8.6PeriodicTrendsintheSizeofAtomsandEffectiveNuclear
Charge
 Thevaluesusedtodetermineatomicradiiare
experimentalvaluesobtainedfromseveralkindsof
sources,i.e.vanderWaals,covalent,andnonbonding;
atomicradiiareaveragevalues.Insolvingproblems
andhomework,studentsneedtousethevaluesfroma
singlesource,likethebook,togettheanswersinthe
solutionmanual.
 Thepatternoftheplotofradiusvs.atomicnumber
(Figure8.9)iseasytoremember.Theheightofthe
peaks(thealkalimetals)increases;then,thevalues
decreaseacrosseachperiod.
 ConceptualConnection8.4EffectiveNuclearCharge
 Effectivenuclearchargeexplainstheperiodictrends,
especiallytheleft‐to‐righttrend.
MisconceptionsandPitfalls

Thenumberofvalenceelectronsis
easytopredictformain‐group
elementsbutmoredifficultfor
transitionelements.

Someexceptionstothechemical
inertnessofthenoblegaseswillbe
introducedinlaterchapters.

Atomsarenotsolidspheresasthey
oftenappeartobeingraphical
representations.Theirouter
surfacesarethecombinationof
manyorbitals.Theseissues,
combinedwiththeuseof
experimentalvaluesfrombonding
andnonbondingdata,giveriseto
averageatomicradii.
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Chapter8.PeriodicPropertiesoftheElements
LectureOutline
Terms,Concepts,Relationships,Skills 8.7Ions:ElectronConfigurations,Magnetic
Properties,IonicRadii,andIonizationEnergy
 Electronconfigurationsofions
o anions
 addelectronsindicatedby
charge
 fillaccordingtoincreasing
energy
o cations
 removeelectrons
indicatedbycharge
 removeelectronsfirst
fromorbitalswithhighest
n
 oftennotthereverseof
fillingorder
 Ionicradii
o cations:smallerthanneutral
atom
o anions:largerthanneutralatom
 Ionizationenergy
o definition:energyrequiredto
removeanelectronfromagas‐
phaseatom
o increasestotherightacrossa
period
o decreasesdownagroup
o successiveionizationenergiesare
larger
o largejumpinIEwhencore
electronsareremoved
FiguresandSolvedProblems
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Example8.6ElectronConfigurationsand
MagneticPropertiesforIons
Figure8.12SizesofAtomsandTheirCations
Figure8.13SizesofAtomsandTheirAnions
Example8.7IonSize
Figure8.14FirstIonizationEnergyversus
AtomicNumberfortheElementsthroughXenon
Figure8.15TrendsinIonizationEnergy
Example8.8IonizationEnergy
unnumberedfigure:1st,2nd,and3rdionization
energiesofNaandMg
Table8.1SuccessiveValuesofIonization
EnergiesfortheElementsSodiumthroughArgon
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Chapter8.PeriodicPropertiesoftheElements
TeachingTips
SuggestionsandExamples
8.7Ions:ElectronConfigurations,MagneticProperties,Ionic
Radii,andIonizationEnergy
 Anionsfollowthesamegeneralprocedureforwriting
electronconfigurations.Cationswilloftenconfuse
students.Forexample,the4sorbitalisfilledbeforethe
3dorbitalsinaneutralatom,butoneremovesa4s
electronbeforea3delectrontomakethecation.
 Thesizeofionscomparedtotheirneutralatomiseasy
topredictbasedonthecharge.Incations,thegreater
positivechargeinthenucleusincreasestheaverage
attractionforeachelectron.Inanions,thereisalower
averageattractionbetweennucleusandelectrons
comparedtotheneutralatom.
 ConceptualConnection8.5Ions,Isotopes,andAtomic
Size
 Thetrendforfirstionizationenergyisexactlyopposite
thatofradiusbutforthesamereasons.Thepatternof
theplotof1stIEvs.atomicnumberissomewhatofa
mirrorimageoftheplotofradiusvs.atomicnumber;in
theformer,thenoblegasesarethepeaks,whereasthe
alkalimetalsarethepeaksinthelatter.
 Successiveionizationsmakeasteepincreasewhen
coreelectronsareremoved.
 Useisoelectronicpairsortriadsasexamplesto
emphasizethinkingaboutperiodictrendsratherthan
simplymemorizingthem.
 ConceptualConnection8.6IonizationEnergiesand
ChemicalBonding
MisconceptionsandPitfalls

Acommonapproachistoaddan
electrontothepreviousatomwhen
writinganelectronconfiguration.
Ananionfollowsthesame
procedureasforneutralatoms,but
cationsrequireelectron‐removal
fromthehighestn‐valueorbitals.
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Chapter8.PeriodicPropertiesoftheElements
LectureOutline
Terms,Concepts,Relationships,Skills 8.8ElectronAffinitiesandMetallicCharacter
 Electronaffinity
o mostelementsreleaseenergywhen
gaininganelectron
o trendsarenotassimpleastheother
periodictrends
 Metalliccharacter
o decreasestotherightacrossaperiod
o increasesdownagroup
8.9SomeExamplesofPeriodicChemicalBehavior:
TheAlkaliMetals,theHalogens,andtheNobleGases
 Alkalimetals
o properties
o reactions
 Halogens
o properties
o reactions
 Noblegases
o properties
o reactions FiguresandSolvedProblems
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Figure8.16ElectronAffinitiesofSelected
Main‐GroupElements
Figure8.17TrendsinMetallicCharacterI
Figure8.18TrendsinMetallicCharacterII
Example8.9MetallicCharacter
Table8.2PropertiesoftheAlkaliMetals
Figure8.19ReactionofSodiumandChlorine
toFormSodiumChloride
Figure8.20ReactionsoftheAlkaliMetals
withWater
Table8.3PropertiesoftheHalogens
unnumberedfigure:photosofelemental
chlorine,bromine,andiodine
Example8.10AlkaliMetalsandHalogen
Reactions
ChemistryandMedicine:Potassiumiodidein
radiationEmergencies
unnumberedfigure:iodinepillsand
structureofthyroxine
unnumberedfigure:photoofliquidhelium
boiling
Table8.4PropertiesoftheNobleGases
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Chapter8.PeriodicPropertiesoftheElements
TeachingTips
SuggestionsandExamples
8.8ElectronAffinitiesandMetallicCharacter
 Electronaffinitiesgenerallydonotfollowsuchsimple
andregulartrendsasradiusand1stionizationenergy.
Group1Ashowsagoodtrend,butmostperiodsdonot.
 Agraphicshowingthetrendsinmetalliccharacterin
theperiodictablemakesthistrendeasytoremember.
Metalliccharacterismacroscopicpropertyunlikethe
microscopicpropertiesoutlinedintherestofthe
chapter.
 ConceptualConnection8.7PeriodicTrends
8.9SomeExamplesofPeriodicChemicalBehavior:TheAlkali
Metals,theHalogens,andtheNobleGases
 Sincetheperiodictableoftencharacterizesthe
behaviorofgroupsofelements,andsincetheir
commonvalence‐electroncountsdictatechemical
properties,itmakessensetointroducesome
descriptivechemistryatthisstage.Demonstrations,
realorvirtual,willcaptureattentionsincetheyare
exothermicandgenerallyinvolveflames.
MisconceptionsandPitfalls

Thecharacterizationofelementsas
metal,metalloid,ornonmetalrefers
tomacroscopicpropertiesandnot
microscopicones.
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Chapter8.PeriodicPropertiesoftheElements
Additional Problem for Electron Configurations
(Example 8.1)
Write the electron configurations of these elements:
a) S
b) Ar
c) Ca
d) Zn
Solution
S 1s22s22p63s23p4
Sulfur has 16 electrons. Distribute two electrons
into the 1s, 2s, each of the three 2p, and 3s, and
distribute four electrons into the three 3p orbitals.
[Ne] 3s23p4
Solution
Ar 1s22s22p63s23p6
Argon has 18 electrons. Distribute two electrons
into the 1s, 2s, each of the three 2p, 3s, and each
of the three 3p orbitals.
[Ar]
Solution
Calcium has 20 electrons. Distribute two electrons
into the 1s, 2s, each of the three 2p, 3s, each of the
three 3p, and 4s orbitals.
Ca 1s22s22p63s23p64s2
[Ar] 4s2
Solution
Zinc has 30 electrons. Distribute two electrons into
the 1s, 2s, each of the three 2p, 3s, each of the
three 3p, 4s, and each of the five 3d orbitals.
Zn 1s22s22p63s23p64s23d10
[Ar] 4s23d10
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Chapter8.PeriodicPropertiesoftheElements
Write the electron configurations of these elements
and identify the core and valence electrons.
Additional Problem for Valence Electrons and
Core Electrons (Example 8.3)
a) Sr
b) Ar
c) Ca
d) Zn
Solution
Strontium has 38 electrons. Distribute two
electrons into the 1s, 2s, each of the three 2p, 3s,
each of the three 3p, 4s, each of the five 3d, each
of the three 4p, and 5s orbitals. For strontium, the n
= 1, 2, 3, and 4 principal quantum levels are
complete or full. The n = 5 level is outermost.
Sr 1s22s22p63s23p64s23d104p65s2
core = 36 electrons, [Kr]
valence = 2 electrons
Solution
Bromine has 35 electrons. Distribute two electrons
into the 1s, 2s, each of the three 2p, 3s, each of the
three 3p, 4s, and each of the five 3d, and distribute
5 electrons into the three 4p orbitals. For bromine,
the n = 1, 2, and 3 principal quantum levels are
complete or full. The n = 4 level is outermost.
Br 1s22s22p63s23p64s23d104p5
core = 28 electrons, [Ar] 3d10
valence = 7 electrons
Solution
Calcium has 20 electrons. Distribute two electrons
into the 1s, 2s, each of the three 2p, 3s, each of the
three 3p, and 4s orbitals. For calcium, the n = 1, 2,
and 3 principal quantum levels are complete or full.
The n = 4 level is outermost.
Ca 1s22s22p63s23p64s2
core = 18 electrons, [Ar]
valence = 2 electrons
Solution
Zinc has 30 electrons. Distribute two electrons into
the 1s, 2s, each of the three 2p, 3s, each of the
three 3p, 4s, and each of the five 3d orbitals. For
zinc, the n = 1, 2, and 3 principal quantum levels
are complete or full. The n = 4 level is outermost.
Zn 1s22s22p63s23p64s23d10
core = 28 electrons [Ar] 3d10
valence = 2 electrons
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Chapter8.PeriodicPropertiesoftheElements
On the basis of periodic trends, choose the
SMALLER atom from each pair:
Additional Problem for Atomic Size (Example
8.5)
a) Sr or Ca
Solution
Strontium is below calcium in Group 2A. As you
move down a group, orbitals are occupied in higher
principal quantum number levels, resulting in a
larger radius.
b) Ar or Kr
1A 2A H Be Mg Ca Sr Ba Calcium is smaller.
Solution
Argon is above krypton in Group 8A. As you move
down a group, orbitals are occupied in higher
principal quantum number levels, resulting in a
larger radius.
7A 8A F He Ne Ar Kr Xn Rn Argon is smaller.
Solution
Calcium (Group 2A) is to the right of potassium
(Group 1A). As you move right across a period, the
effective nuclear charge experienced by outermost
electrons increases, resulting in a smaller radius.
1A 2A H Be K Ca Calcium is smaller.
Solution
6A
Oxygen (Group 6A) is to the left of fluorine (Group
7A). As you move right across a period, the
effective nuclear charge experienced by outermost
electrons increases, resulting in a smaller radius.
O 7A
F 8A
He Ne Fluorine is smaller.
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c) Ca or K
d) O or F
Chapter8.PeriodicPropertiesoftheElements
Additional Problem for Alkali Metal and Halogen
Reactions (Example 8.10)
Write a balanced equation for each of these cases: a) The reaction between sodium metal and bromine gas.
b) The reaction between potassium metal and water. c) The reaction between hydrogen gas and chlorine gas. d) The reaction between calcium and water. Solution
2 Na(s) + Br 2 (g)  2 NaBr(s)
Alkali metals react with halogens to form metal
halides. Write the reagents and products using
their correct forms. Balance the equation.
Solution
Alkali metals react with water to form the alkali
metal cation, hydroxide, and hydrogen gas. Write
the reagents and products using their correct forms.
Balance the equation.
2 K(s) + 2 H 2 O(l)  2 K+(aq) + 2 OH(aq) +
H 2 (g)
Solution
Halogens react with each other or with hydrogen to
form the interhalogen compound or hydrogen
halide, respectively. Write the reagents and
products using their correct forms. Balance the
equation.
H 2 (g) + Cl 2 (g)  2 HCl(g)
Solution
Alkali earth metals react much like the alkali metals.
They react with water to form the alkali earth metal
cation, hydroxide and hydrogen gas. Write the
reagents and products using their correct forms.
Balance the equation.
Ca(s) + 2 H 2 O(l)  Ca2+(aq) + OH(aq) +
H 2 (g)
123
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