atomic strucure：原子结构

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1、ATOMICSTRUCUREThebeginning:1.Dalton’sAtomicTheory–18082.Thomson’sAtomicModel–18973.Rutherford’sAtomicModel–19114.Bohr’sAtomicModel–19135.QuantumMechanicalModel–UsefulInformation:BriefDescriptionMaxPlanck(1900)Radiationemittedbyheatingsolidstovarioustemp

2、eratures.Theenergyemittedbyatomsormoleculesisalwaysinwholenumbermultiplesofenergyofcertainwell-definedquantities.ThewordQuantaorQuantumreferstothesmallestquantityofenergythatcanbeemittedorabsorbedintheformofelectromagneticradiation.E=hn,wherehisPlanck’s

3、constant=6.63x10-34JsWaveVibratingdisturbancebywhichenergyistransmitted.Speedofwavedependsontypeofwaveandthenatureofmediumthroughwhichthewaveistraveling.JamesMaxwell(1873)Electromagneticwavehasanelectricandmagneticfieldcomponent.Bothhavesamewavelengthan

4、dfrequency.ElectromagneticSpectrumRangeofenergies,forexample,ultravioletradiation,infrared,x-rays,radiowaves,gammarays,visible(ROYGBIV)ElectromagneticwavesAllelectromagneticwavestravelatthespeedoflightinavacuum.3.0x108m/sAlbertEinstein(1905)Proposedtheo

5、rytoexplainthephotoelectriceffect.Einstein’stheoryoflightstatesthatabeamoflightbehavesasastreamofparticlesratherthanwavelike.HecalledthestreamofparticlesPHOTONS.Lateritwasproposedthatlightbehavesaseitheraswavesorparticles.Thispropertyisalsoacharacterist

6、icofallmatter.NielsBohr(1913)Atomicstructurewasanaloguestoplanetarysystem.Studiedlinespectraofhydrogeningasphase.Linespectraduetotheexcitationofelectronsfromlowerenergyleveltoahigherone.Whentheelectronfallstoalowerenergylevelorgroundstateitemitsaspecifi

7、camountofenergy.ThelinespectraarenotrestrictedtothevisiblerangebutalsoextendintotheUVandIRrange.Theenergiesassociatedwithelectronmotioninpermittedorbitsarefixedinvalue.ThereforeenergiesareQUANTIZED.LouisDebroglie(1924)Ifwavescanbehavelikeastreamofpartic

8、les(photons)thensocananelectronpossesswavelikeproperties.Aparticleinmotioncanbetreatedasawaveandviseversa.BriefDescriptionDavisson,Germer,G.PThomsonExperimentallyprovedthatelectronspossesswave-likeproperties.WernerHeisenbergHeise