ChemicalBonding化学链接ppt课件.ppt

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1、7ChemicalBonding化学键结1ChapterGoals1.LewisDotFormulasofAtoms路易斯电子点结构式IonicBonding离子键结2.FormationofIonicCompounds形成离子化合物CovalentBonding共价键结3.FormationofCovalentBonds形成共价键4.BondLengthsandBondEnergies键长及键能5.LewisFormulasforMoleculesandPolyatomicIons分子极多元子离子之

2、路易斯结构式6.WritingLewisFormulas:TheOctetRule八隅体法则7.FormalCharges形式电荷8.WritingLewisFormulas:LimitationsoftheOctetRule八隅体法则之限制9.Resonance共振10.PolarandNonpolarCovalentBonds极性及非极性共价键结11.DipoleMoments偶极距12.TheContinuousRangeofBondingTypes键结形式之连续范围2IntroductionA

3、ttractiveforcesthatholdatomstogetherincompoundsarecalledchemicalbonds(化合物中将原子拉进的吸引力称之为化学键结)Theelectronsinvolvedinbondingareusuallythoseintheoutermost(valence)shell(与键结有关的电子通常是指最外层的电子)3IntroductionChemicalbondsareclassifiedintotwotypes:Ionicbonding离子键结re

4、sultsfromelectrostaticattractionsamongions,whichareformedbythetransferofoneormoreelectronsfromoneatomtoanother.离子键为阳离子与阴离子间之库伦静电力，阳离子由金属失去电子形成，阴离子由非金属得到电子形成。两正负电荷之离子吸引力，称为离子键。Ioniccompound离子化合物NaClCovalentbonding共价键结resultsfromsharingoneormoreelectronpa

5、irsbetweentwoatoms.价键为两原子共享电子对之化学键，其结合原子皆为非金属原子CovalentcompoundH2,Cl24IonicCompound离子化合物CovalentCompound共价化合物SolidsGases,liquid,orsolidsHighmeltingpoints(>400oC)Lowmeltingpoints(<300oC)Solubleinpolarsolvents,suchaswaterinsolubleinpolarsolventsinsolublei

6、nnonpolarsolvents,suchasC6H14andCCl4Mostaresolubleinnonpolarsolvents,suchasC6H14,CCl4MoltencompoundsconductelectricitywellbecausetheycontainionsLiquidandmoltencompoundsdonotconductelectricityAqueoussolutionsconductelectricitywellbecausetheycontainionsAq

7、ueoussolutionsareusuallypoorconductorsTwoelementswithdifferentelectronegativities,usuallyametalandanonmetalTwoelementswithsimilarelectronegativities,usuallynonmetals5LewisDotFormulasofAtoms原子的路易斯电子点结构式LewisdotformulasorLewisdotrepresentationsareaconveni

8、entbookkeepingmethodfortrackingvalenceelectrons价电子.Theelectronsintheoutermostoccupiedshells(最外层的电子数)sandporbitalsValenceelectronsarethoseelectronsthataretransferredorinvolvedinchemicalbonding(价电子是指与化学键结有关或转移的电子)Theyarechemicallyi