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ChemicalBondingChemicalBondingChemicalbond:attractiveforceholdingtwoormoreatomstogether.Covalentbondresultsfromsharingelectronsbetweentheatoms.Usuallyfoundbetweennonmetals.Ionicbondresultsfromthetransferofelectronsfromametaltoanonmetal.Metallicbond:attractiveforceholdingpuremetalstogether.ChemicalBonds,LewisSymbols,andtheOctetRuleChemicalBonds,LewisSymbols,Figure8.3:IonicBondingFigure8.3:IonicBondingFigure8.5:CovalentBondingFigure8.5:CovalentBondingChemicalBondsBondTypeSingleDoubleTriple#ofe’s246Notation

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Bondorder123BondstrengthIncreasesfromSingletoTripleBondlengthDecreasesfromSingletoTripleChemicalBondsBondTypeSichemicalBonding化学键解析课件StrengthsofCovalentBondsStrengthsofCovalentBondsLewisSymbolsChemicalBonds,LewisSymbols,andtheOctetRuleLewisSymbolsChemicalBonds,LTheOctetRuleAllnoblegasesexceptHehasans2p6configuration.Octetrule:atomstendtogain,lose,orshareelectronsuntiltheyaresurroundedby8valenceelectrons(4electronpairs).Caution:therearemanyexceptionstotheoctetrule.ChemicalBonds,LewisSymbols,andtheOctetRuleTheOctetRuleChemicalBonds,BondPolarityandElectronegativityElectronegativityElectronegativity:Theabilityofoneatomsinamoleculetoattractelectronstoitself.Paulingsetelectronegativitiesonascalefrom0.7(Cs)to4.0(F).Electronegativityincreasesacrossaperiodanddownagroup.BondPolarityandElectronegatFigure8.6:ElectronegativitiesofElementsElectronegativityFigure8.6:ElectronegativitiBondPolarityandElectronegativityFigure8.7:ElectronegativityandBondPolarityThereisnosharpdistinctionbetweenbondingtypes.Thepositiveend(orpole)inapolarbondisrepresented+andthenegativepole-.HyperChemBondPolarityandElectronegatDrawingLewisStructuresFollowStepbyStepMethod(SeeNgWeb-site)Totalallvalenceelectrons.[ConsiderCharge]Writesymbolsfortheatomsandguessskeletonstructure[defineacentralatom].Placeapairofelectronsineachbond.Completeoctetsofsurroundingatoms.[H=2only]Placeleftoverelectronsinpairsonthecentralatom.Iftherearenotenoughelectronstogivethecentralatomanoctet,lookformultiplebondsbytransferringelectronsuntileachatomhaseightelectronsaroundit.HyperChemCyberChem(Lewis)videoDrawingLewisStructuresFollowLewisStructures–Examples-ILewisStructures–Examples-LewisStructures–Examples-IILewisStructures–Examples-LewisStructures–Examples-IIILewisStructures–Examples-LewisStructures–Examples-IVLewisStructures–Examples-ExceptionstotheOctetRuleCentralAtomsHavingLessthananOctetRelativelyrare.MoleculeswithlessthananoctetaretypicalforcompoundsofGroups1A,2A,and3A.MosttypicalexampleisBF3.FormalchargesindicatethattheLewisstructurewithanincompleteoctetismoreimportantthantheoneswithdoublebonds.ExceptionstotheOctetRuleCeExceptions–CentralAtoms-LessthananOctetExceptions–CentralAtoms-LExceptionstotheOctetRuleCentralAtomsHavingMorethananOctetThisisthelargestclassofexceptions.Atomsfromthe3rdperiodonwardscanaccommodatemorethananoctet.Beyondthethirdperiod,thed-orbitalsarelowenoughinenergytoparticipateinbondingandaccepttheextraelectrondensity.HyperChemExceptionstotheOctetRuleCeExceptions–CentralAtoms-GreaterthananOctetExceptions–CentralAtoms-GTherearefivefundamentalgeometriesformolecularshape:MolecularShapes:VSEPRMolecularShapes:VSEPRMolecularShapes–3DNotationsVSEPR(Ballons)-MovieClipMolecularShapes–3DNotationFigure9.3HyperChemFigure9.3HyperChemSummaryofVSEPRMolecularShapese-pairsNotationNameofVSEPRshapeExamples2AX2LinearHgCl2,ZnI2,CS2,CO23AX3TrigonalplanarBF3,GaI3AX2ENon-linear(Bent)SO2,SnCl24AX4TetrahedralCCl4,CH4,BF4-AX3E(Trigonal)PyramidalNH3,OH3-AX2E2Non-Linear(Bent)H2O,SeCl25AX5TrigonalbipyramidalPCl5,PF5AX4EDistortedtetrahedral(see-sawed)TeCl4,SF4AX3E2T-ShapedClF3,BrF3AX2E3LinearI3-,ICl2-

6AX6OctahedralSF6,PF6-AX5ESquarePyramidalIF5,BrF5AX4E2SquarePlanarICl4-,BrF4-SeeNgWeb-siteHyperChemCyberChmGemsSummaryofVSEPRMolecularShaExamples:VSEPRMolecularShapes-IExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes–I–F08Examples:VSEPRMolecularShaExamples:VSEPRMolecularShapes-IIExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes–II–F08Examples:VSEPRMolecularShaExamples:VSEPRMolecularShapes-IIIExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes–III–F08HyperChemExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes-IVExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes-IVExamples:VSEPRMolecularSha TheEffectofNonbondingElectronsByexperiment,theH-X-HbondangledecreasesonmovingfromCtoNtoO:Sinceelectronsinabondareattractedbytwonuclei,theydonotrepelasmuchaslonepairs.Therefore,thebondangledecreasesasthenumberoflonepairsincreasesVSEPRModelHyperChem TheEffectofNonbondingElecFigure9.10:ShapesofLargerMoleculesInaceticacid,CH3COOH,therearethreecentralatoms.VSEPRModelHyperChemFigure9.10:ShapesofLargerShapesofLargerMoleculesInglycine(simplestaminoacid),NH2CH2CO2H,therearefourpossiblecentralatoms.DrawtheLewisStructureandthe3DVSEPRMolecularGeometryforglycine.Indicatethenameoftheshapeforallpossiblecentralatoms,includingestimationofbondangles.Hint1:Designatethe2ndcarbonintheformulaasthecentralatominskeletonstructure.Hint2:Theacidportionofglycineisthesameasthatofaceticacid.Lewis-VSEPRHWfor10/30/09.Due11/2/09.HyperChemShapesofLargerMoleculesLewiFigure8.10:DrawingLewisStructuresResonanceStructuresFigure8.10:DrawingLewisStFigure9.12HyperChemFigure9.12HyperChemFigure9.11:MolecularShapeandMolecularPolarityHyperChemFigure9.11:MolecularShapeFigure9.13:MolecularShapeandMolecularPolarityHyperChemFigure9.13:MolecularShapeLewisstructuresandVSEPRdonotexplainwhyabondforms.Howdoweaccountforshapeintermsofquantummechanics?Whataretheorbitalsthatareinvolvedinbonding?WeuseValenceBondTheory:Bondsformwhenorbitalsonatomsoverlap.Therearetwoelectronsofoppositespinintheorbitaloverlap.CovalentBondingandOrbitalOverlapGems-MovieClipCovalentBondingandOrbitalOFigure9.14:CovalentBondingandOrbitalOverlapFigure9.14:CovalentBondingchemicalBonding化学键解析课件chemicalBonding化学键解析课件Todeterminetheelectronpairgeometry:drawtheLewisstructure,countthetotalnumberofelectronpairsaroundthecentralatom,arrangetheelectronpairsinoneoftheabovegeometriestominimizee--e-repulsion,andcountmultiplebondsasonebondingpair.VSEPRModel(Figure9.6)VSEPRModel(Figure9.6)VSEPRModelVSEPRModelchemicalBonding化学键解析课件chemicalBonding化学键解析课件DrawingLewisStructuresFormalChargeConsider:ForC:Thereare4valenceelectrons(fromperiodictable).IntheLewisstructurethereare2nonbondingelectronsand3fromthetriplebond.Thereare5electronsfromtheLewisstructure.Formalcharge:4-5=-1.DrawingLewisStructuresFormalDrawingLewisStructuresFormalChargeConsider:ForN:Thereare5valenceelectrons.IntheLewisstructurethereare2nonbondingelectronsand3fromthetriplebond.Thereare5electronsfromtheLewisstructure.Formalcharge=5-5=0.Wewrite:CyberChmGemsDrawingLewisStructuresFormalChemicalBondingLewisAXEnotationVSEPRshapesPolarityChemicalBondingLewisAXEnotatChemicalBondingChemicalBondingChemicalbond:attractiveforceholdingtwoormoreatomstogether.Covalentbondresultsfromsharingelectronsbetweentheatoms.Usuallyfoundbetweennonmetals.Ionicbondresultsfromthetransferofelectronsfromametaltoanonmetal.Metallicbond:attractiveforceholdingpuremetalstogether.ChemicalBonds,LewisSymbols,andtheOctetRuleChemicalBonds,LewisSymbols,Figure8.3:IonicBondingFigure8.3:IonicBondingFigure8.5:CovalentBondingFigure8.5:CovalentBondingChemicalBondsBondTypeSingleDoubleTriple#ofe’s246Notation

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Bondorder123BondstrengthIncreasesfromSingletoTripleBondlengthDecreasesfromSingletoTripleChemicalBondsBondTypeSichemicalBonding化学键解析课件StrengthsofCovalentBondsStrengthsofCovalentBondsLewisSymbolsChemicalBonds,LewisSymbols,andtheOctetRuleLewisSymbolsChemicalBonds,LTheOctetRuleAllnoblegasesexceptHehasans2p6configuration.Octetrule:atomstendtogain,lose,orshareelectronsuntiltheyaresurroundedby8valenceelectrons(4electronpairs).Caution:therearemanyexceptionstotheoctetrule.ChemicalBonds,LewisSymbols,andtheOctetRuleTheOctetRuleChemicalBonds,BondPolarityandElectronegativityElectronegativityElectronegativity:Theabilityofoneatomsinamoleculetoattractelectronstoitself.Paulingsetelectronegativitiesonascalefrom0.7(Cs)to4.0(F).Electronegativityincreasesacrossaperiodanddownagroup.BondPolarityandElectronegatFigure8.6:ElectronegativitiesofElementsElectronegativityFigure8.6:ElectronegativitiBondPolarityandElectronegativityFigure8.7:ElectronegativityandBondPolarityThereisnosharpdistinctionbetweenbondingtypes.Thepositiveend(orpole)inapolarbondisrepresented+andthenegativepole-.HyperChemBondPolarityandElectronegatDrawingLewisStructuresFollowStepbyStepMethod(SeeNgWeb-site)Totalallvalenceelectrons.[ConsiderCharge]Writesymbolsfortheatomsandguessskeletonstructure[defineacentralatom].Placeapairofelectronsineachbond.Completeoctetsofsurroundingatoms.[H=2only]Placeleftoverelectronsinpairsonthecentralatom.Iftherearenotenoughelectronstogivethecentralatomanoctet,lookformultiplebondsbytransferringelectronsuntileachatomhaseightelectronsaroundit.HyperChemCyberChem(Lewis)videoDrawingLewisStructuresFollowLewisStructures–Examples-ILewisStructures–Examples-LewisStructures–Examples-IILewisStructures–Examples-LewisStructures–Examples-IIILewisStructures–Examples-LewisStructures–Examples-IVLewisStructures–Examples-ExceptionstotheOctetRuleCentralAtomsHavingLessthananOctetRelativelyrare.MoleculeswithlessthananoctetaretypicalforcompoundsofGroups1A,2A,and3A.MosttypicalexampleisBF3.FormalchargesindicatethattheLewisstructurewithanincompleteoctetismoreimportantthantheoneswithdoublebonds.ExceptionstotheOctetRuleCeExceptions–CentralAtoms-LessthananOctetExceptions–CentralAtoms-LExceptionstotheOctetRuleCentralAtomsHavingMorethananOctetThisisthelargestclassofexceptions.Atomsfromthe3rdperiodonwardscanaccommodatemorethananoctet.Beyondthethirdperiod,thed-orbitalsarelowenoughinenergytoparticipateinbondingandaccepttheextraelectrondensity.HyperChemExceptionstotheOctetRuleCeExceptions–CentralAtoms-GreaterthananOctetExceptions–CentralAtoms-GTherearefivefundamentalgeometriesformolecularshape:MolecularShapes:VSEPRMolecularShapes:VSEPRMolecularShapes–3DNotationsVSEPR(Ballons)-MovieClipMolecularShapes–3DNotationFigure9.3HyperChemFigure9.3HyperChemSummaryofVSEPRMolecularShapese-pairsNotationNameofVSEPRshapeExamples2AX2LinearHgCl2,ZnI2,CS2,CO23AX3TrigonalplanarBF3,GaI3AX2ENon-linear(Bent)SO2,SnCl24AX4TetrahedralCCl4,CH4,BF4-AX3E(Trigonal)PyramidalNH3,OH3-AX2E2Non-Linear(Bent)H2O,SeCl25AX5TrigonalbipyramidalPCl5,PF5AX4EDistortedtetrahedral(see-sawed)TeCl4,SF4AX3E2T-ShapedClF3,BrF3AX2E3LinearI3-,ICl2-

6AX6OctahedralSF6,PF6-AX5ESquarePyramidalIF5,BrF5AX4E2SquarePlanarICl4-,BrF4-SeeNgWeb-siteHyperChemCyberChmGemsSummaryofVSEPRMolecularShaExamples:VSEPRMolecularShapes-IExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes–I–F08Examples:VSEPRMolecularShaExamples:VSEPRMolecularShapes-IIExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes–II–F08Examples:VSEPRMolecularShaExamples:VSEPRMolecularShapes-IIIExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes–III–F08HyperChemExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes-IVExamples:VSEPRMolecularShaExamples:VSEPRMolecularShapes-IVExamples:VSEPRMolecularSha TheEffectofNonbondingElectronsByexperiment,theH-X-HbondangledecreasesonmovingfromCtoNtoO:Sinceelectronsinabondareattractedbytwonuclei,theydonotrepelasmuchaslonepairs.Therefore,thebondangledecreasesasthenumberoflonepairsincreasesVSEPRModelHyperChem TheEffectofNonbondingElecFigure9.10:ShapesofLargerMoleculesInaceticacid,CH3COOH,therearethreecentralatoms.VSEPRModelHyperChemFigure9.10:ShapesofLargerShapesofLargerMoleculesInglycine(simplestaminoacid),NH2CH2CO2H,therearefourpossiblecentralatoms.DrawtheLewisStructureandthe3DVSEPRMolecularGeometryforglycine.Indicatethenameoftheshapeforallpossiblecentralatoms,includingestimationofbondangles.Hint1:Designatethe2ndcarbonintheformulaasthecentralatominskeletonstructure.Hint2:Theacidportionofglycineisthesameasthatofaceticacid.Lewis-VSEPRHWfor10/30/09.Due11/2/09.HyperChemShapesofLargerMoleculesLewiFigure8.10:DrawingLewisStructuresResonanceStructuresFigure8.10:DrawingLewisStFigure9.12HyperChemFigure9.12HyperChemFigure9.11:MolecularShapeandMolecularPolarityHyperChemFigure9.11:MolecularShapeFigure9.13:MolecularShapeandMolecularPolarityHyperChe

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