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Course: CHEM 211, Fall 2011
School: George Mason
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GeorgeMasonUniversity GeneralChemistry211 Chapter8 ElectronConfigurationandChemicalPeriodicity Acknowledgements CourseText:Chemistry:theMolecularNatureofMatterand Change,6thedition,2011,MartinS.Silberberg,McGrawHill 04/22/12 TheChemistry211/212GeneralChemistrycoursestaughtat GeorgeMasonareintendedforthosestudentsenrolledinascience /engineeringorientedcurricula,withparticularemphasison...

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GeorgeMasonUniversity GeneralChemistry211 Chapter8 ElectronConfigurationandChemicalPeriodicity Acknowledgements CourseText:Chemistry:theMolecularNatureofMatterand Change,6thedition,2011,MartinS.Silberberg,McGrawHill 04/22/12 TheChemistry211/212GeneralChemistrycoursestaughtat GeorgeMasonareintendedforthosestudentsenrolledinascience /engineeringorientedcurricula,withparticularemphasison chemistry,biochemistry,andbiologyThematerialontheseslidesis takenprimarilyfromthecoursetextbuttheinstructorhasmodified, condensed,orotherwisereorganizedselectedmaterial. Additionalmaterialfromothersourcesmayalsobeincluded. Interpretationofcoursematerialtoclarifyconceptsandsolutionsto problemsisthesoleresponsibilityofthisinstructor. 1 ElectronConfiguration&Chemical Periodicity DevelopmentofthePeriodicTable CharacteristicsofManyElectronAtoms ThePauliExclusionPrinciple TheElectronSpinQuantumNumber ElectrostaticEffectsandEnergyLevelSplitting DevelopmentoftheQuantumMechanicalModelofthe PeriodicTable BuildingupofPeriod3 ElectronConfigurationWithinGroups BuildingupPeriod4 04/22/12 BuildingupofPeriods1&2 GeneralPrinciplesofElectronConfiguration UnusualConfigurations:TransitionandInnerTransition 2 ElectronConfiguration&Chemical Periodicity TrendsinThreeKeyAtomicProperties 04/22/12 TrendsinIonizationEnergy(IA) TrendsinAtomicSize TrendsinElectronAffinity(EA) AtomicStructureandChemicalReactivity 3 ElectronConfiguration TheworkofBalmer(Rydbergequation)andBohr (BohrPostulates)invokedtheideathatspectra linesofcompoundsrepresenteddifferent wavelengths(Balmer)andenergylevels(Bohr)of theradiation. 1 1 1 = R 2 - 2 2 n2 04/22/12 E = h = - 2.18 10 -18 1-1 J2 n n2 i f Eachenergylevelwasdesignatedbythewhole numberinteger,n. ncouldhaveanyvaluefrom1 (infinity) 4 ElectronConfiguration FollowingtheworkofBalmer,Bohr,andEinstein, deBroglie,Heisenbergandmanyothersdeveloped QuantumMechanics Quantummechanics,alsoknownasquantumphysicsor quantumtheory,isabranchofphysicsprovidinga mathematicaldescriptionofthewaveparticledualityof matterandenergy Inquantumchemistryeachatomisdistinguishedbyits uniquenumberofelectrons,whichismatchedbyanequal numberorprotonsinthenucleus(atomicnumber,Z). Newelementsaredefinedbytheiruniquenumberof electronseachnewelementhasonemoreelectronthan itspredecessor 04/22/12 5 ElectronicConfiguration Theelectronsareconfigured(distributed)intoorbitals, whichrepresentenergylevels Electronsareabletomovefromoneorbital(energylevel) toanotherbyemissionorabsorptionofaquantumof energy,intheformofaphoton Knowledgeoftheelectronconfigurationofdifferentatoms isusefulinunderstandingthestructureoftheperiodic tableofelements. Theconceptisalsousefulfordescribingthechemical bondsthatholdatomstogether. Inbulkmaterialsthissameideahelpsexplainthepeculiar propertiesoflasersandsemiconductors. 04/22/12 6 ElectronConfiguration Accordingtoquantummechanicseachelectronis describedby4quantumnumbers PrincipalQuantumNumber (n) AngularMomentumQuantumNumber MagneticQuantumNumber SpinQuantumNumber (ms) (l) (ml) Thefirstthreequantumnumbersdefinethewave functionoftheelectronsatomicorbital,i.e.,itsize andgeneralenergylevel Thefourthquantumnumberreferstothespin orientationofthe2electronsthatoccupyan 04/22/12 7 ElectronicConfiguration QuantumNumbersandAtomicOrbitals ThePrincipalQuantumNumber(n)represents theShellNumberinwhichanelectronresides Itrepresentstherelativesizeoftheorbital EquivalenttoperiodicchartPeriodNumber Definestheprincipalenergyoftheelectron Thesmallernis,thesmallertheorbital Thesmallernis,thelowertheenergyofthe electron ncanhaveanypositivevaluefrom 1,2,3,4 (Currently,n=7isthemaximumknown) 04/22/12 8 ElectronicConfiguration QuantumNumbersandAtomicOrbitals(Cont) TheAngularMomentumQuantumNumber(l) distinguishessubshellswithinagivenshell Eachmainshell,designatedbyquantum numbern,issubdividedinto: l=n1subshells (l)canhaveanyintegervaluefrom0ton1 Thedifferentlvaluescorrespondtothe s,p,d,fdesignationsusedintheelectronic configurationoftheelements Letterspdf 04/22/12 9 ElectronicConfiguration QuantumNumbersandAtomicOrbitals(Cont) TheMagneticQuantumNumber(ml)defines atomicorbitalswithinagivensubshell Eachvalueoftheangularmomentumnumber(l) determinesthenumberofatomicorbitals Foragivenvalueofl,mlcanhaveanyinteger valuefromlto+l ml=lto+l 04/22/12 Eachorbitalhasadifferentshapeand orientation(x, y, z)inspace Eachorbitalwithinagivenangularmomentum numbersubshell(l)hasthesameenergy 10 ElectronConfiguration QuantumNumbersandAtomicOrbitals(Cont) TheSpinQuantumNumber(ms)referstothe twopossiblespinorientationsoftheelectrons residingwithinagivenatomicorbital Eachatomicorbitalcanholdonlytwo(2) electrons Eachelectronhasaspinorientationvalue Thespinvaluesmustopposeoneanother Thepossiblevaluesofmsspinvaluesare: +1/2and1/2 04/22/12 11 SternGerlachExperiment AbeamofHatomscanbeseparatedinto2beamsof oppositeelectronspininamagneticfield ms(1/2)electronshaveaslightlygreaterenergythan ms(+1/2)electrons 04/22/12 12 Representationofelectronspin Aspinningchargedparticlealignsinamagneticfield dependingonspinstate 04/22/12 13 SummaryofQuantumNumbers Name Symbol Permitted Values positiveintegers (1,2,3,) Property principal n angular momentum l integersfrom 0n1 orbitalshape Thelvalues 0,1,2,and3 correspondto s,p,d,f orbitals,respectively magnetic ml integersfrom l0+l orbitalorientation spin ms +1/2or1/2 directionofespin 04/22/12 orbitalenergy (size) 14 SummaryofQuantumNumbers Name,Symbol (Property) AllowedValues Principal,n (size,energy) Angular momentum,l (shape) Magnetic,ml (orientation) QuantumNumbers Positiveinteger n=1 (1,2,3,...) n=2 n=3 l =0n1 0(s),1(p), 2(d),3(f) l=0 (1s) l=0 (2s) l=1 (2p) l,,0,,+l 0 0 1 0 +1 l=0 (3s) 0 1 2 04/22/12 l=1 (3p) l=2 (3d) 0 +1 1 0 +1 +2 15 ElectronConfiguration Anelectronconfigurationofanatomisaparticular distributionofelectronsamongavailablesubshells Theconfigurationnotationliststhesubshellsymbols(s, p,d,f)sequentiallywithasuperscriptindicatingthe numberofelectronsoccupyingthatsubshell Ex:lithium(Period2,AtomicNo3)has 2electrons inthe 1ssubshell 1electron inthe 2ssubshell 1s22s1 Fluorine(Period2,AtomicNo9)has 2electronsinthe 2electronsinthe 04/22/12 1ssubshell 2ssubshell 5electronsinthe 2psubshell 16 ElectronConfiguration Auniquesetofthe1st3quantumnumbers(n,l,m l) definesanOrbital Anorbitalcancontainamaximumof2electrons,each withadifferentspin(+1/2or1/2) Anorbitaldiagramisnotationusedtoshowhowthe orbitalsofasubshellareoccupiedbyelectrons Eachorbitalisrepresentedbyacircle Eachorbitalcanhaveamaximumof2electrons Eachgroupoforbitalsislabeledbyits SubShellNotation(s,p,d,f) Electronsarerepresentedbyarrows: up()forms=+1/2anddown( )forms=1/2 04/22/12 1s 2s 2p 17 ThePauliExclusionPrinciple ThePauliExclusionPrinciple Notwoelectronsinanatomcanhavethesamefour quantumnumbers Anorbital(uniquecombinationofn,l,ml) canhold,atmost,twoelectrons TwoelectronsinthesameOrbitalhaveoppositespins 1/2+1/2 04/22/12 18 ThePauliExclusionPrinciple Themaximumnumberofelectronsandtheir orbitaldiagramsare: Sub Sub Shell Shell No. No. Orbitals Values (-l to +l) Max No. Max Electrons Electrons s (l = 0) 0) 1 (0) 2 p (l = 1) 1) 3 (-1, 0, +1) 6 d (l =2) 5 (-2,-1,0,+1,+2) 10 f (l =3) =3) 7 (-3,-2,1,0,+1,+2,+3) 14 04/22/12 19 NobleGasElectronic Configurations Inthefollowingslideselectronicconfigurationsofthe elementsinthePeriodicTablewillbediscussed Electronicconfigurationscanbecomequitecomplex (lengthy)astheAtomicNumberincreases AcondensedformoftheElectronicConfigurationofa givenelementorionisoftenused Asymbol,[X],representingtheelectronconfigurationof theNoblegasintheperiodjustabovetheelementof interestissubstitutedforthedetailconfiguration ThefollowingslideillustratestheNobleGas configurationsandtheCondensedFormsymbolused withotherelements 04/22/12 20 Configurationsandthe PeriodicTable CondensedElectronicConfigurations FullElectronicConfiguration Condensed Electronic Helium 1s Configuration [He] 2 e- Neon 1s22s22p6 [Ne] 10 e- Argon Argon 1s22s22p63s23p6 1s [Ar] 18 e- Krypton 1s22s22p63s23p63d104s24p6 [Kr] 36 e- Xenon Xenon 1s22s22p63s23p63d104s24p64d105s25p6 [Ze] 54 e- Beryllium 1s22s2 Magnesium 1s22s22p63s2 [He] 2s24 e2s [Ne] 3s2 12 e3s Calcium [Ar] 4s2 20 e4s 2 1s22s22p63s23p64s2 Sodium Ion (Na)1s22s22p63s1(Na+)1s22s22p6+1e 04/22/12 [Ne]+1e 21 ElectronConfiguration QuantumNumbern=1(Period1) lvalues=0to(n1)=0to(11)=0 l=0(sorbital) mlvalues=l,0,+l=0(1sorbital) msvalues=1/2&+1/2(2electronsperorbital) Z = 1 Hydrogen 1s1 or 1s1 Z = 2 Helium 1s2 or 1s2 or 1sorbitals Thus,forn=1thereisoneorbital(s)whichcanaccommodate2 elements n =Principalquantumnumber(size,energy) l =AngularMomentum(orbitalshape) 0(s),1(p),2(d),3(f) ml =magnetic(orbitalorientation) ms 04/22/12 =Spin(direction) values =1,2,3. values =0n1 values =l...0...+l values =1/2&+1/2 22 ElectronConfiguration QuantumNumbern=2(Period2) lvalues =0to(n1)=0to(21)=0to1 l=0(s),1(p) Forl=0(s)ml=0(one2sorbital,2electrons) msvalues=1/2&+1/2 Forl=1(p)ml=10+1(three2porbitals,6electrons) msvalues=1/2&+1/2ineachorbital 2sorbitals Z=3 Lithium 1s22s1 or [He]2s1 Z=4 Beryllium 1s22s2 or [He]2s2 Z=5 Boron 1s22s2p1 or [He]2s22p1 Z=6 Carbon 1s22s2p2 or [He]2s22p2 Z=7 Nitrogen 1s22s2p3 or [He]2s22p3 Z=8 Oxygen 1s22s2p4 or [He]2s22p4 Z=9 Fluorine 1s22s2p5 or [He]2s22p5 1s22s2p6 or [He]2s22p6 Z=10 Neon 04/22/12 2porbitals 23 ElectronConfiguration Withsodium(Z=11),the3ssubshellbeginsto fill Z=11 Sodium 1s22s22p63s1 or [Ne]3s1 Z=12 Magnesium 1s22s22p63s2 or [Ne]3s2 Starting with Z = 13, the 3p sub shell begins to fill Z=13 Aluminum 1s22s22p63s23p1 or [Ne]3s23p1 Z=18 or [Ne]3s23p6 04/22/12 Argon 1s22s22p63s23p6 24 ElectronConfiguration ElectrostaticEffectsandEnergyLevelSplitting Theprincipalquantumnumber(n)definestheenergy levelofanatom Theuniquevaluesoftheprincipalquantumnumbersof multielectronatoms(n,l,ml)defineauniqueenergy levelfortheorbitalofagivenelectron 04/22/12 Thehigherthenvalue,thehighertheenergylevel Theenergyofagivenorbitaldependsmostlyonthe valueoftheprincipalquantumnumber(n),i.e.itssize, andtoalesserdegreeontheshapeoftheorbital representedbythevariousvaluesofthemagnetic quantumnumber(l) 25 ElectronConfiguration Theenergystatesofmultielectronatomsarisefrom 2counteractingforces: NucleusElectronAttractions ElectronElectronRepulsion Nuclearprotonscreatepull(attraction)onelectrons Highernuclearcharge(Z)lowersorbitalenergy (stabilizessystem)byincreasingnucleuselectron attractions 04/22/12 Theenergyrequiredtoremovethe1selectronfrom hydrogen(H),Z=1,ismuchlessthantheenergyto removethe1selectronfromtheLi2+ion,Z=3 26 ElectronConfiguration EffectofNuclearCharge(Z)onOrbitalEnergy GreaterNuclearChargelowersorbitalenergy makingitmoredifficulttoremovetheelectron fromorbit Theabsolutevalueofthe1sorbitalenergyis relateddirectlytoZ2 Energyrequiredtoremove1selectronfromH 1311kJ/mol(Z=+1,Leaststable) Energyrequiredtoremove1selectronfromHe+ 5250kJ/mol(Z=+2) Energyrequiredtoremove1selectronfromLi+ 11815kJ/mol(Z=+3,Moststable) 04/22/12 27 ElectronConfiguration ShieldingEffectofElectronRepulsionsonOrbital Energy Electronsfeelrepulsionfromotherelectronssomewhat shielding(counteracting)theattractionofnuclear protons Shielding(screening)lowersthefullnuclearchargetoan EffectiveNuclearCharge(Zeff) ThelowertheEffectiveNuclearCharge,theeasieritisto removeanelectron 04/22/12 Ittakeslessthanhalfasmuchenergytoremovean electronfromHelium(He)(2373kJ/mol)thanfromHe+ (5250kJ/mol)becausethesecondelectroninHerepels thefirstelectronandeffectivelyshieldsthefirstelectron fromthefullnuclearcharge(lowerZeff) 28 ElectronConfiguration Penetration:Effectsoforbitalshape Theshapeofanatomicorbitalaffectshowclosean electronmovesclosertonucleus,i.e.,thelevelof penetration Penetrationandtheresultingeffectsofshieldingona atomicorbitalcausestheenergylevel(n)tobesplit intosublevelsofdifferingenergyrepresentingthe variousvaluesofthemagneticquantumnumber(l) Thelowerthevalueofthemagneticquantumnumber (l),themoreitselectronspenetrate OrderofSublevelEnergies s(l=0)<p(l=1)<d(l=2)<f(l=3) 04/22/12 Eachoftheorbitalsforagivenvalueofl (ml=l0+l)hasthesameenergy 29 AufbauPrinciple AufbauPrincipleschemeusedtoreproducethe groundstateelectronconfigurationsofatomsbyfollowing thebuildinguporderbasedonrelativeenergylevelsof quantumsubshells Thebuildingupordercorrespondsforthemostpartto increasingenergyofthesubshells Byfillingorbitalsofthelowestenergyfirst,youusuallyget thelowesttotalenergy(groundstate)oftheatom 04/22/12 30 AufbauPrinciple Listedbelowistheorderinwhichallthepossiblesubshells fillwithelectrons NotetheorderdoesNOTfollowastrictnumericalsubshell order 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f Youneednotmemorizethisorder Thenextslideprovidesapictorialprovidinganeasierwayof theviewingthebuilduporder 04/22/12 31 OrderforFillingAtomicSubshells Writesubshellsinrowsof increasingn Period n=1 n=2 n=3 n=4 n=5 n=6 04/22/12 1s 2s 3s 4s 5s 6s Arrangebyincreasing AngularMomentum(l) 2p 3p 4p 5p 6p Drawaseriesofdiagonals 3d 4d 4f 5d 5f 6d 6f Orderoffillingistheorder inwhichdiagonalsstrike subshells Notethe4ssubshellis filledbeforethe3d subshellbecausethe4s electronsareatlower energylevelsthanthe 3delectrons 32 AufbauPrinciple Everyatomhasaninfinitenumberofpossibleelectron configurations(electronscanberaisedtoanynumberof energy(n)levels) Theconfigurationassociatedwiththelowestenergy leveloftheatomiscalledthe groundstate Otherconfigurationscorrespondto excitedstates 04/22/12 Tablesonthenext3slideslistthegroundstate configurationsofatomsuptokrypton 33 PartialOrbitalDiagrams PartialOrbitalDiagrams 04/22/12 34 PartialOrbitalDiagrams Chromium(Cr)relativetoVanadium(V) TheCr4s1subshellisfilledbeforethe3dsubshelliscompleted An[Ar]3d44s2orbitalconfigurationwouldbeexpectedforground stateCr,butthe[Ar]3d54s1orbitalislowerinenergy Cr 04/22/12 35 PartialOrbitalDiagrams Copper(Cu)relativetoNickel(Ni) Copperwouldbeexpectedtohaveagroundstate configurationof[Ar]3d94s2 The[Ar]3d104s1configurationisactuallylowerinenergy Ni Cu 04/22/12 36 OrbitalEnergyLevelsin MultielectronSystems 3d 4s Energy 3p 3s 2p 2s 1s 04/22/12 3dorbitalswouldbe expectedtobefilledbefore 4sorbitals Actualorderoffilling dependsontotalground stateenergyoftheatom 3dand4sorbitalsarevery closeinenergy Selected4s,5s,6s,7s levelsarefilledbefore3d, 4d,4f,5f,respectively (seeslides18&19) 37 04/22/12 Configurationsandthe PeriodicTable Electronsthatresideintheoutermostshellofanatom orinotherwords,thoseelectronsoutsidethenoblegas corearecalledvalenceelectrons Theseelectronsareprimarilyinvolvedinchemical reactions Elementswithinagivengrouphavethesamevalence shellconfiguration Thisaccountsforthesimilarityofthechemical propertiesamonggroupsofelements Noblegascore:aninnershellconfigurationresembling oneofthenoblegases(He,Ne,Ar,Kr,Xn) Pseudonoblegascore:noblegascore+(n1)d10 electrons:ExSnSn+4 Sn([Kr]5s24d105p2)Sn+4([Kr]4d10+4e 38 Configurationsandthe PeriodicTable ConfigurationsofMainGroupIons Noblegaseshavefilledouterenergylevels(ns2np6), haveveryhighIonizationEnergies(IEs),andpositive (endothermic)ElectronAffinities(EAs);thusdonot readilyformions ElementsinGroups1A,2A,6A,7Athatreadilyform ionsbygainingelectrons(1A&2A)orlosingelectrons (6A&7A)attainafilledouterlevelconformingtoa NobleGasconfiguration SuchionsaresaidtobeIsoelectronicwiththe nearestNoblegasconfiguration Na(1s22s22p63s1)Na+(1s22s22p6)+1e 04/22/12 Isoelectronicwith[Ne]+1e 39 Configurationsandthe PeriodicTable Theenergyneededtoremovetheelectronsfrommetalin groups1A,2A,6A,7A,issuppliedduringexothermic reactionswithnonmetals Attemptstoremovemorethan1electronfromgroup1A or2electronsfromgroup2Ametalswouldmean removingcore(notvalence)electronsrequiring significantlymoreenergythanisavailablefromareaction withanonmetal 04/22/12 40 Configurationsandthe PeriodicTable ThelargermetalsfromGroups3A,4A,and5Aform cationsthroughadifferentprocess Itwouldbeenergeticallyimpossibleforthemtolose enoughelectronstoattainanoblegasconfiguration Ex:Tin(Sn),Z=50wouldhavetolose14electrons(two 5p,ten4d,two5s)tobeisoelectronicwithKrypton:Z=36 Instead,tinlosesfewerelectronsandstillattainsoneor morestablepseudonoblegasconfigurations Sn([Kr]5s24d105p2)Sn4+([Kr]4d10)+4e Stabilitycomesfromempty5s&5psublevels andafilledinner4dsublevel(n1)d10configuration PseudoNobleGasConfiguration 04/22/12 41 PracticeProblem Whichofthefollowingelectronconfigurationsrepresentsan excitedstate? a.He:1s2 b.Ne:1s22s22p6 c.Na:1s22s22p63s1 d.P:1s22s22p63s23p24s1 e.N:1s22s22p3 Ans:d GroundstateforPhosphorusis: 1s22s22p63s23p3 Thepsubshellwouldcontinuetofillbefore the4ssubshellwouldstarttofill 04/22/12 42 PracticeProblem Whatistheelectronconfigurationforthevalenceelectronsof Technetium(Tc,Z=43)? a.4d55s2 d.4d65s2 Ans:a b.5s25d4 c.4s24d4 e.3d44s2 4d55s25+2=7valenceelectrons Technetium(atomicno.=43=43totalelectrons) SelectNobleGasConfigurationclosestto43 1s22s22p63s23p63d104s24p6[Kr]36e [Kr]+4d55s2=36+7=43=Technetium 04/22/12 43 PracticeProblem Whatistheelectronconfigurationforthevalenceelectronsof Polonium(Po,Z=84)? a.6s26p2 b.6s25d106p4 c.6s25d106p6 d.6s26p4 e.7s26p4 Ans:b 6s25d106p42+10+4=16valenceelectrons Polonium(atomicno.84=84totalelectrons) SelectNobleGasConfigurationclosestto84 Xenon1s22s22p63s23p63d104s24p64d105s25p6[Ze]54e 8454=30electronswhichmustinclude14electronsthat fillinthe4forbitalsthatstartwithLanthanum 3014=16=6s25d106p4 04/22/12 44 Configurationsandthe PeriodicTable Thefollowingslideillustrateshowtheperiodictable providesasoundwaytoremembertheAufbausequence Youcandeterminethisfromtheirpositiononthe periodictable 04/22/12 Inmanycasesyouneedonlytheconfigurationofthe outerelectrons Thetotalnumberofvalenceelectronsforanatom equalsitsgroup(verticalcolumn)number 45 Configurationsandthe PeriodicTable Mainblock=s+pblocks sblockpblock dblock TransitionElements fblock InnerTransition Elements 04/22/12 46 OrbitalDiagrams Considercarbon(Z=6)withthegroundstate configuration1s22s22p2 Threepossiblearrangementsaregiveninthefollowing orbitaldiagrams. 1s 2s 2p Diagram 1: Diagram 2: Diagram 3: 04/22/12 Each state has a different energy and different magnetic characteristics 47 OrbitalDiagrams Hundsrulestatesthatthelowestenergyarrangement (thegroundstate)ofelectronsinasubshellisobtained byputtingelectronsintoseparateorbitalsofthesubshell withthesamespinbeforepairingelectrons Lookingatcarbonagain,weseethatthegroundstate configurationcorrespondstodiagram1whenfollowing Hundsrule 1s 04/22/12 2s 2p 48 OrbitalDiagrams ToapplyHundsruletoOxygen,whosegroundstate configurationis1s22s22p4,placethefirstsevenelectrons asfollows 1s 2p The last electron is paired with one of the 2p electrons to give a doubly occupied orbital. 1s 04/22/12 2s 2s 2p 49 Summary PauliExclusionprinciple:no2esinanatomcanhave thesamefourquantumnumbers AufbauPrinciple:obtainelectronconfigurationsofthe groundstateofatomsbysuccessivelyfillingsubshells withelectronsinaspecificorder HundsRule:thelowestenergyarrangementofelectrons inasubshellisobtainedbyputtingelectronsinto separateorbitalsofthesubshellwiththesamespin beforeparingthem Recall:+1/2spinhaslowerenergythen1/2spin (seeslide5) 04/22/12 50 PeriodicProperties Twofactorsdeterminethesizeofanatom Onefactoristheprincipalquantumnumber,n.The largernis,thelargerthesizeoftheorbital Theotherfactoristheeffectivenuclearcharge(slide 19),whichisthepositivechargeanelectron experiencesfromthenucleusminusanyshielding effectsfrominterveningelectrons ThePeriodicLawstatesthat: Whentheelementsarearrangedbyatomicnumber,their physicalandchemicalpropertiesvaryperiodically AtomicSize,IonizationEnergy,ElectronAffinity 04/22/12 51 PeriodicPropertiesAtomicSize Atomicradius 04/22/12 WithineachPeriod(acrosshorizontalrow),theatomic radiustendstodecreasewithincreasingatomic number(nuclearchargemoredominantthanelectron repulsion) WithineachGroup(downaverticalcolumn),the atomicradiustendstoincreasewithincreasingperiod number(electronrepulsiondominatesnuclearcharge increase) 52 PeriodicPropertiesAtomicSize 04/22/12 Representationofatomicradii(covalentradii)of themaingroupelements(neutralatoms) 53 PeriodicPropertiesAtomicSize ElementsvsIons IonicSizeincreasedown agroup Numberofenergy levelsincreases IonicSizebecomesmore complicatedacrossa period Increasedramatically withfirstanion 04/22/12 Decreasesamong cations Decreaseswithin anions 54 PeriodicPropertiesAtomicSize IonicSizeandAtomicSize Cationsaresmallerthantheirparentatoms Electronsareremovedfromtheouterlevel Resultingdecreaseinelectronrepulsions allowsnuclearchargetopullremaining electronscloser Anionsarelargerthantheirparentatoms Electronsaddedtoouterlevel Resultinginincreasedelectronrepulsion 04/22/12 allowingthemtooccupymorespace 55 PeriodicPropertiesIonizationEnergy Ionizationenergy Thefirstionizationenergyofanatomistheminimal energyneededtoremovethehighestenergy (outermost)electronfromtheneutralatom ForaLithiumatom,thefirstionizationenergyis illustratedby: Li(1s22s1)Li+(1s2)+eIE=520kJ/mol Endothermic(requiresenergyinput) 04/22/12 56 PeriodicPropertiesIonizationEnergy Ionizationenergy(IE) Thisfollowsthetrendinsize,asitismoredifficultto removeanelectronthatisclosertothenucleus 04/22/12 Thereisageneraltrendthationizationenergies increasewithatomicnumberwithinagivenperiod Forthesamereason,wefindthationizationenergies, againfollowingthetrendinsize,decreasedescending downacolumnofelements 57 IonizationEnergyvsAtomicNumber NoblegaseshavehighestIEs AlkalimetalshavelowestIEs 04/22/12 58 PeriodicPropertiesIonizationEnergy IonizationEnergiestotheRightoftheaverticallinecorrespondtoremovalof electronsfromtheCoreoftheatom 04/22/12 59 PeriodicPropertiesIonizationEnergy Ionizationenergy(IE) Theenergiesrequiredateachstepareknownasthe firstionizationenergy,thesecondionizationenergy, andsoforth 04/22/12 Theelectronsofanatomcanberemovedsuccessively SuccessiveIonizationEnergiesincreasebecauseeach electronispulledawayfromanionwithaprogressively higherpositivecharge,i.e.,amoreeffectivenuclear charge 60 ExceptionstoIonizationEnergyTrends AIIIAelement,suchasBoron(2s22p1),hasasmaller ionizationenergy(IE)thantheprecedingIIAelement Beryllium(2s2)becauseonenpelectronismoreeasily removedthanthesecondnselectron AVIAelement,suchasoxygen(2s22p4),hassmaller ionizationEnergythantheprecedingVAelementnitrogen (2s22p3).Asaresultofrepulsionitiseasiertoremovean electronfromthedoublyoccupied2porbitaloftheVI elementthatfromasinglyoccupiedporbitalofthe precedingVAelement Nitrogen2s22p3 04/22/12 Oxygen2s22p4 61 PeriodicPropertiesElectronAffinity ElectronAffinity(EA):theenergychangeforthe processofaddinganelectrontoaneutralatominthe gaseousstatetoformanegativeion,i.e.,anAnion 1stElectronAffinityFormationof1moleofmonovalent (1)gaseousions Atoms(g)+eion(g) E=EA1 Fortheformationofthechlorideion(Cl)fromthechlorine atom,thefirstelectronaffinityisillustratedby: Cl([Ne]3s 2 3p 5 ) + e- Cl - ([Ne]3s 2 3p 6 ) Electron Affinity = EA1=349 kJ/mol Exothermic (releases energy) 04/22/12 62 PeriodicPropertiesElectronAffinity ElectronAffinity(EA) Themorenegativetheelectronaffinity,themorestable thenegativeionthatisformed Broadlyspeaking,thegeneraltrendgoesfromlower lefttoupperrightaselectronaffinitiesbecomemore negative Highestelectronaffinitiesoccurforhalogens,FandCl Negativevaluesindicatethat energyisreleasedwhenthe Anionforms Note:ElectronAffinityisnotthe sameasElectronegativity See(Chap9)bondedatom attractingsharedelectronpair 04/22/12 63 PeriodicPropertiesAtomicSize AtomicSize AtomicSize(neutralatoms&ions)increasesdownamaingroup AtomicSize(neutralatoms&ions)decreasesacrossaPeriod AtomicSizeremainsrelativelyconstantacrossatransitionseries IonizationEnergy 1stIonizationEnergydecreasesdownagroup 1stIonizationEnergyincreasesacrossperiod FirstIonizationEnergy(removeoutermoste)isinverselyrelatedto atomicsize SuccessiveIEsshowverylargeincreasesafter1stelectronis removed ElectronAffinity Similarpatterns(withmanyexceptions)toionizationEnergy(lower lefttoupperright) Highestelectronaffinitiesoccurforhalogens,FandCl 04/22/12 64 PeriodicPropertiesSummary 04/22/12 65 AtomicStructure/ChemicalReactivity Metals Metalsarelocatedintheleftandlowerthree quartersofthePeriodicTable TypicalProperties ShinySolids HighMeltingPoints GoodThermal&ElectricalConductors MalleableDrawnintowiresandrolledinto sheets Loseelectronstononmetals 04/22/12 66 AtomicStructure/ChemicalReactivity NonMetals NotShiny LowMeltingPoints PoorThermal&ElectricalConductors CrumblySolidsorgases 04/22/12 Nonmetalsarelocatedintheupperright quarterofthePeriodicTable GainElectronsfromMetals 67 AtomicStructure/ChemicalReactivity Metalloids(semimetals) LocatedbetweenMetals&NonMetalsinthe PeriodicChart boron,silicon,germanium,arsenic, antimony,tellurium,andpolonium 04/22/12 Anelementthatexhibitstheexternal characteristicsofametal,butbehaves chemicallymoreasanonmetal Arsenic,forexample,isametalloidthathas thevisualappearanceofametal,butisapoor conductorofelectricity Theintermediateconductivityofmetalloids 68 AtomicStructure/ChemicalReactivity Metalloids(semimetals) Theelectronegativitiesandionizationenergies ofthemetalloidsarebetweenthoseofthe metalsandnonmetals,sothemetalloids exhibitcharacteristicsofbothclasses Thereactivityofthemetalloidsdependsonthe elementwithwhichtheyarereacting Ex.Boron Actsasanonmetalwhenreactingwith sodium 04/22/12 69 AtomicStructure/ChemicalReactivity Metalloids(semimetals) Theboilingpoints,meltingpoints,anddensities ofthemetalloidsvarywidely Asarule,metalloidsdonotformmultiplebonds Compoundscontainingtheseelementswill oftenshowanincompleteoctetaroundthe centralatom 04/22/12 70 AtomicStructure/ChemicalReactivity MetallicBehaviordecreasefromlefttorightand increasesfromtoptobottominPeriodicTables NonMetals TransitionElements fblockInnerTransitionElements 04/22/12 71 AtomicStructure/ChemicalReactivity MetallicBehavior MetalstendtoLoseelectrons Metalstendtoloseelectronsduringchemical reactionsbecausetheyhaveLowionization energiescomparedtononmetals Elementsgenerallytendtoincreasetheir metalliccharactergoingdownaPeriodicTable group Thegreatestcontrastinchangingmetallic characterisingroups3A6A ElementsatthetoptendtoformAnions, 04/22/12 72 AtomicStructure/ChemicalReactivity MetallicBehavior(Cont) Arsenic(As)(period4)&Antimony(Sb)(period 5)aremetalloidsandgenerallydonotform ions 04/22/12 Nitrogen(N)&Phosphorus(P),bothnon metalstendtoform3anions Bismuth(Bi)(period6)isatypicalmetal formingmostlyioniccompoundsasa3+cation 73 AtomicStructure/ChemicalReactivity MetalBehavior(Cont) Metallicbehaviordecreasesgoingfromleftto rightacrossthePeriodtable Increasinggroupnumber(lefttoright) Abilitytoloseelectrons(formcations) becomesmoredifficultwithasIonization Energy(IE)increases Abilitytogainelectrons(formanions) increasesasElectronAffinity(EA) decreases(becomesmorenegative) Elementsontheleft(moremetallic)tendto 04/22/12 formpositivelychargedCations 74 AtomicStructure/ChemicalReactivity MetallicBehavior(Cont) Sodium(Na)group1VeryMetallic Readilyloseselectron(Na+ion)whichreacts immediatelywithoxygentoformanoxide Aluminum(Al)group3Metalloid FormsomeAl3+ioniccompounds,butis covalentlybondedinothers Silicon(Si)group4Metalliod Doesnotoccurasamonoatomicion 04/22/12 Phosphorus(P)group5nonmetal Formsafew3ions 75 AtomicStructure/ChemicalReactivity MetallicBehavior(Cont) AcidBaseBehaviorofElementOxides Metals Mostmaingroupmetalstransferelectronsto oxygenformingionicoxides Ionicoxidesactasbasesproducing OH(hydroxide)ionsfromO2 Nonmetals Shareelectronswithoxygentoformcovalent oxides 04/22/12 Covalentoxidesactasacidsproducing 76 AtomicStructure/ChemicalReactivity MetallicBehavior(Cont) AmphotericBehavior Somemetalsandmanymetalloidsform oxidesthatcanactaseitheranacidora base 04/22/12 77 AtomicStructure/ChemicalReactivity AcidBasebehaviorofcommonoxides Aselementsbecomemoremetallicgoingdown agroup,theoxidesbecomemorebasic NitrogenPentoxide(N2O5) Period2nonmetallicformsnitricacid,a strongacid N2O5(s)+H2O(l)2HNO3(aq) Tetraphosphorusdecaoxide(P4O10) SlightlymoremetallicPeriod3nonmetal formsaweakeracid 04/22/12 78 AtomicStructure/ChemicalReactivity AcidBasebehaviorofcommonoxides ArsenicPentoxide(As2O5) Group4metalloid(moremetallic)isweakly basic BismuthPentoxide(Bi2O5) Group5metalloid(mostmetallicingroup) Basicoxide,insolubleinwater,formssalt& waterwithanacid Bi2O3(s)+6HNO3(aq)2Bi(NO3)3(aq)+ 3H2O(l) 04/22/12 79 AtomicStructure/ChemicalReactivity AcidBasebehaviorofcommonoxides Acrossagroup Elementsbecomelessmetallicacrossa group Oxidesbecomesmoreacidic MetallicSodium(Na)(group1)&Magnesium (Mg)(group2)formstronglybasicoxides MetallicAluminum(group3)formsamphoteric aluminumoxide(Al2O3),whichcanactasa basetoreactwithanacidorasanacidto reactwithabase 04/22/12 80 AtomicStructure/ChemicalReactivity AcidBasebehaviorofcommonoxides Acrossagroup(Cont) SiliconDioxide(SiO4)group4 Weaklyacidicformingsalt&waterwitha base SiO2(s)+2NaOH(aq)Na2SiO3(aq)+ H2O(l) CommonoxidesofPhosphous(group5) 04/22/12 Sulfur(group6)andChlorine(group7)are increasinglyacidicformingincreasingly strongeracids 81 AtomicStructure/ChemicalReactivity AcidBasebehaviorofcommonoxides TrendsinacidbasebehaviorofGroup5and Period3oxides RedAcidic(nonmetaloxides) BlueBasic(metaloxides) OtherMetalloidoxides(notegradations) i ze y icS sicit m a Ato deB y lic i tal nerg Ox eE M ore ation M iz Ion 04/22/12 82 AtomicStructure/ChemicalReactivity PropertiesofMonoatomicIons ElectronConfigurationofMainGroupions Recall:ElementsinGroups1&2readily loseelectronstoformcationsandelements ingroups6&7readilygainelectronstoform anions Theformationoftheanionsorcationsresult inafilledoutershell,i.e.,thenearestnoble gasconfiguration Na(1s22s22p63s1)Na+(1s22s22p6)Ne+e Br([Ar]4s23d104p5)+eBr([Ar]4s23d104p6) 04/22/12 ([Ar]4s23d104p6)[Kr] 83 AtomicStructure/ChemicalReactivity PropertiesofMonoatomicIons(Cont) ElectronConfigurationofMainGroupions RemovingmorethanoneelectronfromNatoform Na2+ortwoelectronsfromMgtoformMg3+means removingcore(nonvalence)electrons,which requiresmuchmoreenergythanisavailablefromthe chemicalreaction 04/22/12 Energytoremovetheoutervalenceshellelectrons (IonizationEnergy)issuppliedduringtheexothermic reactionofametalwithanonmetal Similarly,adding2electronstoFluorinetoformF2 meansaddingelectronstothenextenergylevel, whichwouldrequirealargeamountofenergyto overcometheshieldingofthenuclearchargebythe 18innercoreelectrons 84 AtomicStructure/ChemicalReactivity PropertiesofMonoatomicIons ElectronConfigurationofMainGroupions LargerMetalsofGroups3,4,5 Energeticallyimpossibleforthemtoloseenough electronstoattainnoblegasconfiguration Tin(Sn)[Kr]5s25p24d10wouldhavetolose14 electrons(two5p,ten4d,andtwo5s)tobe isoelectronicwithKrypton(Kr)[Ar]4s24p6 Cationsformedthroughadifferentprocess 04/22/12 Sn+4lossoftwo5s&two5pelectrons, attainingstabilityfromthefilledin4dsublevel Sn+2lossoftwo5pelectrons,attaining 85 AtomicStructure/ChemicalReactivity PropertiesofMonoatomicIons ElectronConfigurationofMainGroupions LargerMetalsofGroups3,4,5 Carbon 04/22/12 Wouldhavetoeitherlose4electronsto attaintheC4+Heliumconfigurationor gain4electronstoattaintheC4Neon configuration Ineithercase,theenergyrequirements areextremelyhigh,i.e.sunlike 6 86 AtomicStructure/ChemicalReactivity PropertiesofMonoatomicIons ElectronConfigurationofMainGroupions MostelementsthatformMonatomicionsthat areIsoelectronicwithanoblegaslieinthe fourgroupsthatflankgroup8 04/22/12 87 PracticeProblem Usingcondensedelectronconfigurations,write reactionsfortheformationofthecommonionsof thefollowing: Iodine: I([Kr]5s24d105p5)+eI([Kr]5s24d105p6)I[Xe] Potassium: K([Ar]4s1)K+([Ar])+e Indium: Group3Aloses3electronsorloses1electron 04/22/12 In([Kr]5s24d105p1)In3+([Kr]4d10)+3e 88 AtomicStructure/ChemicalReactivity ElectronConfigurationsofTransitionMetalIons Transitionmetalionsrarelyattainnoblegas configurations Energyrequiredtoattainnoblegasconfigurationis veryhigh Exceptions 04/22/12 ScandiumformsSc3+;TitaniumformsTi4+ InPeriods4&5,atransitionmetalcanform morethanonecationbylosingallofitsnsand someofthe(n1)delectrons 89 AtomicStructure/ChemicalReactivity ElectronConfigurationsofTransitionMetalIons Aufbauelectronbuildup AtthebeginningofPeriod4,the4sorbitalisnearerthe nucleusthanthe3dorbitalmakingitmorestablethanthe empty3dorbital Thefirst&secondelectronsfillthe4sorbitalbeforefilling theempty3dorbitals 04/22/12 Atthebeginningofthetransitionelements(group3B), however,thepreviouslyfilled4sorbitalsdonotdoavery goodjobofshieldingthe3delectrons The3dorbitalsnowbecomemorestablethanthe4s orbitalsandbegintofillundertheinfluenceofincreased nuclearchargeacrossoverinorbitalenergy 90 AtomicStructure/ChemicalReactivity ElectronConfigurationsofTransitionMetalIons Aufbauelectronbuildup(Cont) The4selectrons,whichwereaddedbeforethe3d electrons,arenowlostpreferentiallybeforethe3d electronstoformthetransitionmetalelectrons SimpleRulesforformingtheionofanyMainGroupor TransitionGroupelement Formaingroup,sblockmetals,removeallelectrons withthehighestnvalue Formaingroup,pblockmetals,removenp electronsbeforenselectrons 04/22/12 Electronswiththehighestnvalueareremovedfirst Fortransition(dblock)metals,removenselectrons before(n1)delectrons 91 MagneticProperties Aspinningelectronbehaveslikeatinymagnetgeneratinga magneticfield Asingleelectron(unpaired)inanorbitalcanbeaffectedbyan externallyappliedmagneticfield AParamagneticelement(orion)has1ormoreorbitalswith unpairedelectronsandisweaklyattractedbyamagneticfield Titanium[Ar]4s23d2 4s 4p 3d 4p ADiamagneticelement(orion)hasonlypairedelectronsand isnotattractedbyamagneticfield CopperionCu+[Ar]4s23d10 04/22/12 3d 4s 92 AtomicStructure/ChemicalReactivity MagneticPropertiesofTransitionMetalIons Ag(Z=47)[Kr]5s14d10 5s Unpaired Paramagnetic byappliedmagneticfield Cd(Z=48)[Kr]5s24d10 Paired magnetic 04/22/12 5s Diamagnetic 4d 5p 4d split 5p notsplitbyapplied field 93 AtomicStructure/ChemicalReactivity UsingParamagnetismtoverifyelectronconfiguration Titanium(Ti)[Ar]4s23d2 Titanium(II)Ion(Ti2+)([Ar]3d2)+2e Paramagnetic Ti 4s 3d 4p Unpairede Paramagnetic Ti2+ 4s 3d 4p Unpairede IfTitaniumhadlostitstwo3delectrons,theTitaniumIonwouldhave beendiamagnetic(allelectronsshared) TheTitaniumIonactuallyshowspropertiesofParamagnetism (Themassofthetitaniumionisaffectedwhenplacedinamagneticfield) 04/22/12 94 AtomicStructure/ChemicalReactivity IncreasingParamagnetism Iron(Fe)IronIII(Fe3+) Fe([Ar]4s23d6)Fe3+([Ar]3d5)+3e Fe 4s 3d 4p 4s 3d 4p Fe3+ Thelossofthe24selectronsand oneofitspaired3delectrons resultsinincreasedparamagnetism 04/22/12 95 PracticeProblem Usecondensedelectronconfigurationtowritethereaction fortheformationofMn2+ion,andpredictwhethertheionis paramagnetic ManganeseMn(Z=25) Mn([Ar]4s23d5)Mn2+([Ar]3d5)+2e Mn 4s 3d 4p 4s 3d 4p Mn2+ Rule:Removenselectronsfirst TheMn2+ionisparamagnetic 04/22/12 96 PracticeProblem Usecondensedelectronconfigurationtowritethereaction fortheformationofCr3+ion,andpredictwhethertheionis paramagnetic ChromiumCr(Z=24) Cr([Ar]4s13d5)Cr3+([Ar]3d3)+3e Cr 4s 3d 4p 4s 3d 4p Cr3+ NoteirregularityforCr:4ssubshellfillsbefore3dsubshelliscomplete Rule:Removenselectronsfirst TheCr3+ionisparamagnetic 04/22/12 97 SummaryEquations N=Principalquantumnumber(size,energy) values =1,2,3. l=AngularMomentum(orbitalshape) 0(s),1(p),2(d),3(f) values =0n1 ml=magnetic(orbitalorientation) values =l...0...+l Ms=Spin(direction) values 04/22/12 =1/2&+1/2 98
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George Mason - CHEM - 211
GeorgeMasonUniversityGeneralChemistry211Chapter9ModelsofChemicalBondingAcknowledgementsCourseText:Chemistry:theMolecularNatureofMatterandChange,6thedition,2011,MartinS.Silberberg,McGrawHill04/22/12TheChemistry211/212GeneralChemistrycoursestaughtat
George Mason - CHEM - 211
GeorgeMasonUniversityGeneralChemistry211Chapter10TheShapes(Geometry)ofMoleculesAcknowledgementsCourseText:Chemistry:theMolecularNatureofMatterandChange,6thedition,2011,MartinS.Silberberg,McGrawHill04/22/12TheChemistry211/212GeneralChemistrycourses
George Mason - CHEM - 211
GeorgeMasonUniversityGeneralChemistry211Chapter11TheoriesofCovalentBondingAcknowledgementsCourseText:Chemistry:theMolecularNatureofMatterandChange,6thedition,2011,MartinS.Silberberg,McGrawHill04/22/12TheChemistry211/212GeneralChemistrycoursestaugh
George Mason - CHEM - 211
GeorgeMasonUniversityGeneralChemistry211Chapter12IntermolecularForces:Liquids,Solids,andPhaseChangesAcknowledgementsCourseText:Chemistry:theMolecularNatureofMatterandChange,6thedition,2011,MartinS.Silberberg,McGrawHillTheChemistry211/212GeneralChem
George Mason - CHEM - 211
GENERAL CHEMISTRY I (Chem 211)Lecture SyllabusInstructor: Dr. James C. SchornickCourse:Chemistry 211-004 T 4:30Office Hrs: M, T, W, F9:30 amR2:00 pmT2:00 amTelephone: 703-993-1091Email:jschorni@gmu.edu- 7:10 pm- 11:00 am- 4:00 pm- 4:00 pm
George Mason - CHEM - 211L
Absorption Spectroscopy Spectroscopy - Study of the Interaction ofElectromagnetic Radiation (Energy) andMatter When energy is applied to matter it can beabsorbed, emitted, cause a chemical change(reaction), or be transmitted. Electromagnetic Spectr
George Mason - CHEM - 211L
Anion Cation AnalysisBackgroundAnions- Elements or molecules that have gained electrons.They have negative charge and have been reduced.They can be oxidizing agents in a ReDox reactionCations - Elements or molecules that have lost electrons.They ha
George Mason - CHEM - 211L
Chem 211 laboratoryThis Week October 2, 2003 Synthesis of AspirinNext Week The Ideal Gas LawThis experiment is not in the Slayden lab manualThe instructions for this experiment can be found on theGenchem Website:http:/chem.gmu.edu/resultsUnder Chem
George Mason - CHEM - 211L
GenChem/Organic Chemistry LaboratoryDepartment OfficeRoom343 Science &amp; Technology IMSN3E2Phone703-993-1070FAX703-993-1055Dr. James C. SchornickOffice408A Science &amp; Technology IMailboxRoom 343 Science &amp; Technology IPhone703-993-1091E-Mail
George Mason - CHEM - 211L
Density of SolutionsNext Week Sept 25, 2003Experiment:Empirical Formula of Zinc IodideReferences:Slayden, S, Chem 211, 212, 251 LaboratoryExperiments, 2003, pp. 31 35http:/chem.gmu.edu/results Click on EmpiricalFormulahttp:/classweb.gmu.edu/jscho
George Mason - CHEM - 211L
Hesss Law Heat of Reaction Enthalpy A State of Matter Function Enthalpy Change ( H) in a chemical reaction is the difference between the Heat Contents of the products and the reactants. ( H)rxn = ( H)products - ( H)reactants ( H) associated with a chemica
George Mason - CHEM - 211L
The Ideal Gas lawThe Ideal Gas LawThis experiment is not in the Slayden lab manualThe instructions for this experiment can be found on theGenchem Website:http:/chem.gmu.edu/resultsUnder Chem 211 Handouts click on:Gas Law HandoutGas Law Lab Instruc
George Mason - CHEM - 211L
Chem 211 Laboratory Next Week Oct 2, 2003 Experiment: Synthesis of Aspirin References: Slayden, S, Chem 211, 212, 251 Laboratory Experiments, 2003, pp. 57 - 66 http:/chem.gmu.edu/results Click on Synthesis of Aspirin http:/classweb.gmu.edu/jschorni/chem21
George Mason - CHEM - 211L
VSEPR Theory &amp; Molecular ModelingPurpose- To understand, visualize, and predict the spatialarrangement of molecular shapes.Approach - Use Lewis Dot diagrams, Ball &amp; Stick models, and theValence Shell Electron-Pair Repulsion (VSEPR) theory toconstruc
George Mason - CHEM - 211L
General Chemistry 211 LaboratoryNext WeekExperiment - Density of SolutionsLab Manual - p. 23-29Quiz- Material in Lab Manual and Web SitePrelab- Density ExperimentLab Report- Measurements (Pennies) Experiment is dueMeasurements The Penny Experime
George Mason - CHEM - 211L
Volumetric Analysis - Titration of VinegarVolumetric AnalysisThe quantitative determination of the concentration of one substanceby titration against a substance of known concentration.TitrationA solution of known concentration (the standard) is adde
George Mason - CHEM - 315
IsolationofCaffeineOverviewExtractionofCaffeinefromVivarin,anoverthecountercaffeinetabletAnaqueousVivarin/SodiumCarbonatemixtureisextractedwithDichloromethane(MethyleneChloride)AfterevaporationtodrynesstheproductisrecrystallizedfromAcetone/Petroleu
George Mason - CHEM - 315
SynthesisofCyclohexeneSynthesisofanAlkenebyDehydrationofanAlcoholviaE1(Elimination)MechanismSolomans&amp;Fryle: pp29730204/22/121E1SynthesisofCyclohexeneBackgroundAnEliminationreactionisatypeoforganicreactioninwhichtwosubstituentsareremovedfromamole
George Mason - CHEM - 315
GasChromatographyAcetates04/22/12GasChromatography,RefractiveIndex&amp;Distillation Thenexttwo(2)experimentsintroduceGasChromatographyandSimple&amp;FractionalDistillation. TheyarethentiedtogetheralongwiththeRefractiveIndextechniqueinathirdexperiment.ThisWe
George Mason - CHEM - 315
SpectroscopyBuildingAToolsetForTheIdentificationofOrganicCompoundsPhysicalChemical TestsPropertiesHydrocarbonsMelting PointAlkanesBoiling PointAlkenesDensityAlkynesSolubilityHalidesRefractive IndexAlcoholsAldehydesKetones04/22/12Spect
George Mason - CHEM - 315
InfraredSpectroscopy(IR)LabInfraredSpectroscopyIdentificationofUnknownTheuseofselectedphysicalpropertiesandInfraredSpectroscopytodeterminetheidentityofanunknowncompound.TextMaterialsSlayden pp.3344Pavia pp.851885`(InfraredSpectroscopy)pp.941959(
George Mason - CHEM - 315
GenChem/Organic Chemistry LaboratoryDepartment OfficeRoom343 Science &amp; Technology IMSN3E2Phone703-993-1070FAX703-993-1055Dr. James C. SchornickOfficeRoom 318 Science &amp; Technology IMailboxRoom 343 Science &amp; Technology IPhone703-993-1091E-M
George Mason - CHEM - 315
OrganicQualitativeAnalysisPhysicalProperties,ChemicaltestsandInfraredSpectroscopytoIdentify:UnknownHalide (primary,secondary,tertiary)HydrocarbonAlcohol(alkane,alkene,aromatic)(primary,secondary,tertiary)References:Slayden,S.,Stalick,W.;2010,Cata
George Mason - CHEM - 315
Experiment:Date:Grignard ReagentNamePartnersCourseSectionDrawer No.Laboratory Report Template InstructionsThe first 7 pages of this document contain hints &amp; instructions for using thetemplate and formatting the report. Delete these pages and any
George Mason - CHEM - 315
Recrystallization/FiltrationecrystallizationPurificationofanorganiccompoundbydissolvingasolidinahotsolventandrecrystallizingthecompoundbyslowcoolingacuumFiltrationSeparationofthesolidsolutefromaliquidsolventReferences:Slayden,et.al.,pp.2931PaviaT
George Mason - CHEM - 315
Simple&amp;FractionalDistillationExperimentSimple&amp;FractionalDistillationEvaluationoftherelativeeffectivenessofSimple&amp;FractionalDistillationtoseparatemixturesoforganiccompoundsbasedondifferencesinBoilingPointDeterminationofMole0romDistillateVolumeData,Gas
George Mason - CHEM - 315
TButyl(tPentyl)ChlorideSynthesisSynthesizetButyl(ortPentyl)ChlorideNote:ThisexperimentmayutilizeeithertButylAlcohol(m.p.25.7oC)ortPentylAlcohol(m.p.9.5oC)asoneofthestartingreactants.TextReferencesSlayden PaviaExp#21PaviaTech1204/22/12pp.4950p
George Mason - CHEM - 318
SynthesisofAcetanilideSynthesisofAcetanilideNucleophilicAcylSubstitution(addition/elimination)reactionbetweenAnilineandAceticAnhydrideReferencesPaviaSchornick http:/classweb.gmu.edu/jschorni/chem31804/22/12 p.65681SynthesisofAcetanilideOvervie
George Mason - CHEM - 318
Aldehydes&amp;KetonesClassificationTestsTheuseofChemicalClassificationTests,SelectedPhysicalProperties,NMR,andIRtoIdentifyanUnknownAldehydeorKetoneReferences:Pavia04/22/12Slayden p.7376WebNoteshttp:/classweb.gmu.edu/jschorni/chem318p.4914961Aldehy
George Mason - CHEM - 318
ElectrophilicAromaticSubstitution(BrominationofToluene)Demonstrationoftheeffectofamonosubstitutedelectrondonargroup(ringactivator)onsubsequentsubstitutionofothergroupsontheBenzeneringReferences04/22/12SlaydenLabManual p.7576Website:http:/classweb
George Mason - CHEM - 318
SynthesisofDibenzalacetoneSynthesisofDibenzalacetoneMixedAldolCondensation(ClaisenSchmidt)reactionbetweenAcetoneandBenzaldehydeinthepresenceof95%Ethanoland20%SodiumHydroxideReferences:Pavia04/22/12Slayden p.77Schornick http:/classweb.gmu.edu/jsch
George Mason - CHEM - 318
FriedelCraftsAlkylationPurposePreparationof4,4ditertbutylbiphenylusingtheFriedelCraftsalkylationofBiphenylthroughElectrophilicsubstitutionofaLewisBase(tButylChloride(Haloalkane)inthepresenceofFerricChlorideactingasaLewisAcidReferences:Website:http
George Mason - CHEM - 318
GrignardReagent/ReactionsPreparationofaGrignardReagent(Phenylmagnesiumbromide)andreactionwithCarbonDioxidetoformBenzoicAcidthroughanElectrophilicAdditionreactionReferences:Pavia - p. 303 309; 313 314Schornickhttp:/classweb.gmu.edu/jschorni/chem318
George Mason - CHEM - 318
SynthesisofIsopentyl(Amyl)AcetateEster(BananaOil)OverviewSynthesisAcid(H2SO4)catalyzedFischerEsterificationreactionofaCarboxylicAcid(AceticAcid)withtheHydroxylgroupofanAlcohol(Isopentyl[amyl]Alcohol).ThisisaCondensationreactionwherethemoleculesbecom
George Mason - CHEM - 318
NitrationofMethylBenzoateDemonstrationoftheeffectofanelectronwithdrawinggrouponamonosubstitutedbenzeneringonsubsequentsubstitutionofothergroupsontheBenzeneringReferences:04/22/12Pavia,etal. pp352357Slayden,etal. pp67691NitrationofMethylBenzoate
George Mason - CHEM - 318
Organic Chemistry LaboratoryBuildingAToolsetForTheIdentificationofOrganicCompoundsPhysicalPropertiesMeltingPointBoilingPointDensitySolubilityRefractiveIndex04/22/12ChemicalTestsHydrocarbonsAlkanesAlkenesAlkynesHalidesAlcoholsAldehydesKe
George Mason - CHEM - 318
SpectroscopyExperiment(NMR)DeterminationoftheIdentityofanunknownorganiccompoundusingselectedphysicalproperties,InfraredSpectroscopy,andNMRSpectroscopyUnknownList:pp.126127inSlaydenLabManualReferences Slayden,etal.pp.5960 Pavia,etal. Schornick04/
George Mason - SYST - 220
George Mason - SYST - 220
Log to base 10 usedpage 26xyXlogx12345.119.5467800.301030.4771210.60206Ylog yXYX^2y hat(y-yhat)^2 (y-ybar)^20.70757005.0231.290035 0.388339 0.090619 19.815391.662758 0.793337 0.227645 44.224531.892095 1.139154 0.362476 78.170
George Mason - SYST - 220
SYST 220 Class NotesLecture 1: Discrete Dynamical Models Introduction to ModelingMain point: Similar set of mathematical equations can be used to solve diverse range of real-worldproblemsDiscrete Dynamical Systems ModelingDiscrete: Time is measured i
George Mason - SYST - 220
SYST 220Class NotesLecture 2: Discrete DynamicalReviewword problemdynamical system: a (n + 1) = f (a (n )solve using spreadsheetcobweb analysisfind equilibrium a = f (a )Terminologya (n + 1) = f (a (n ) , First order dynamic systema (0 ) = a 0
George Mason - SYST - 220
SYST 220 Class NotesLecture 3: Discrete Dynamical ModelsReviewAffine system: a (n + 1) = ra (n ) + bSolution isa (n ) = Cr n +b1 requilibrium rn blows up if rn goes to 0 ifr &lt; 1 (stable) rn oscillates ifSolution isr &gt; 1 (unstable)r = 1 (mar
George Mason - SYST - 220
SYST 201 Class NotesLecture 4: Discrete Dynamical ModelsNon-homogeneous Dynamic Systems: Exponential Driving TermsNon-homogeneous Dynamic SystemsSystems so far: a (n +1) = ra (n) + bThis chapter: a (n +1) = ra (n) + g ( n)g(n) can be thought of as a
George Mason - SYST - 220
SYST 220 Class NotesLecture 5: Discrete Dynamical ModelsNon-homogeneous Dynamic Systems: Exponential Driving TermsSection 4.1 (p.160)1 1. Problem Statement:Given: a) a(n +1) = 2a(n) +3nd) a(n+1) = 2a(n) + 3n + 4nf) a(n+1) = 3a(n) +2 * 4n- 6General
George Mason - SYST - 220
Lecture 6: Discrete Dynamical ModelsSecond-order systemsA second-order system is a system in which the present state of the system depends uponthe previous two system states.Example: a (n) = - 3.5a (n - 1) + 2a (n - 2)Note: This system is also equiva
George Mason - SYST - 220
1.26 1.12 (new book)1.33 1.19 (new book)1.42 1.25 (new book)1.43 1.26 (new book)
George Mason - SYST - 220
3.2 a3.4 b Roots are -5 and -5 Steady part is 3 There are 2 exponential terms for the transient part 3.5 c Complex roots with positive real part. UNSTABLE 3.6 b or 3.9 b (new book)
George Mason - SYST - 220
SYST 220: Dynamical Modeling ISpring 2012Systems Engineering and Operations ResearchGeorge Mason UniversityCourse Overview: An important problem in engineering is to predict the behavior of systems thatchange in time. Such systems are called dynamica
George Mason - OR - 649
Meta heuristics Final exam: Due May 9th1) Solve the TSP with GA. Distance in hundreds of miles. Generate an initial population ofsize 3. Use one point cross over and 1 mutation per iteration. Perform at least 5 iterationsNYMiami DallasChicagoNew Yor
George Mason - OR - 649
Metaheuristics Meta Greekwordforupperlevelmethods Heuristics Greekwordheuriskein artofdiscoveringnewstrategiestosolveproblems. ExactandApproximatemethods Exact MathprogrammingLP,IP,NLP,DP Approximate Heuristics Metaheuristicsusedfor Combinatoria
George Mason - OR - 649
MetaheuristicsMeta- Greek word for upper level methodsHeuristics Greek word heuriskein art of discoveringnew strategies to solve problems.Exact and Approximate methodsExactApproximateMath programming LP, IP, NLP, DPHeuristicsMetaheuristics used f
George Mason - OR - 649
MetaheuristicsThe idea: search the solution space directly. No mathmodels, only a set of algorithmic steps, iterative method.Find a feasible solution and improve it. A greedy solutionmay be a good starting point.Goal: Find a near optimal solution in
George Mason - OR - 649
NeighborhoodRepresentation of solutionsVector of Binary values 0/1 Knapsack, 0/1 IP problemsVector of discrete values- Location , and assignment problemsVector of continuous values on a real line continuous,parameter optimizationPermutation sequenci
George Mason - OR - 649
Escaping local optimasAccept nonimproving neighborsIterating with different initial solutionsMultistart local search, greedy randomized adaptive searchprocedure (GRASP), iterative local searchChanging the neighborhoodTabu search and simulated anneal
UC Davis - CHI - 10
Welcome /BienvenidosDr. Lorena V. MarquezIm sitting in My HistoryClass,Im Olivas,Richardsitting in my1989history class,The instructorcommencesrapping,Im in my U.S.History class,And Im on theverge of napping.The MayflowerThe History of Chica
George Mason - OR - 649
Escaping local optimasAccept nonimproving neighborsIterating with different initial solutionsMultistart local search, greedy randomized adaptive searchprocedure (GRASP), iterative local searchChanging the neighborhoodTabu search and simulated anneal
UC Davis - CHI - 10
TheSpanishConquest,1500sBirthofMestizoNation?Conquest:Istheacquisitionofaterritoryanditsinhabitantsthroughwar.Itisaninstitutionthatrequiresenforcinglabor/economicsystems;usurpingoflocalpoliticsandgovernments;andimposingpowerthroughreligion,culture
George Mason - OR - 649
Escaping local optimasAccept nonimproving neighborsIterating with different initial solutionsMultistart local search, greedy randomized adaptive searchprocedure (GRASP), iterative local searchChanging the neighborhoodTabu search and simulated anneal
UC Davis - CHI - 10
Pre-Columbian CivilizationsPopular Image of AztecsIztacchuatl (female) and Popocatptl (male)Bering Strait Ice Bridge Melted, 9000BCIndigenous Diet: Corn, Beans, Chili, andSquashCivilizationIs where people live in large complexagricultural groups w
George Mason - OR - 649
Escaping local optimasAccept nonimproving neighborsIterating with different initial solutionsMultistart local search, greedy randomized adaptive searchprocedure (GRASP), iterative local searchChanging the neighborhoodTabu search and simulated anneal
UC Davis - CHI - 10
American Conquest:A Quest for Manifest DestinyMiguel Hidalgo y CostillaMexican War of Independence,1810-1821What to do with MexicosNorthern Frontier? Increase Population Increase Trade Increase ProductionThe Alamo, 1836Richard Henry Dana, Jr.