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1、AtomicStructureWhatareatoms?Whatareatomsmadeof?Whatparticlesareatomsmadeof?protonsneutronselectronsAtomsaremadeupofthreesmallerparticles:Theelectronsarespreadoutaroundtheedgeoftheatom.Theyorbitthenucleusinlayerscalledshells(energylevels).Theprotonsandneutronsexistinadensec
2、oreatthecentreoftheatom.Thisiscalledthenucleus.Therearetwopropertiesofprotons,neutronsandelectronsthatareespeciallyimportant:masselectricalcharge.Theatomsofanelementcontainequalnumbersofprotonsandelectronsandsohavenooverallcharge.-1almost0electron01neutron+11protonchargema
3、ssparticleMassandelectricalchargePropertiesoftheparticlesoftheatomSummary:theatomsofarThenucleusis:madeupofprotonsandneutronspositivelychargedbecauseoftheprotonsdensebecauseitcontainsallthemassoftheatominatinyspace.Electronsare:verysmallandlight,andnegativelychargedabletob
4、elostorgainedinchemicalreactionsfoundthinlyspreadaroundtheoutsideofthenucleus,orbitinginlayerscalledshells(energylevels).DiscoveringatomicstructureAtomic(proton)numberandmassnumberHowmanyprotons?Eachelementhasadefiniteandfixednumberofprotons.Alltheatomsofaparticularelement
5、alwayscontainthesamenumberofprotons.Forexample:Thenumberofprotonsinanatomisknownastheatomicnumberorprotonnumber.Itisthesmallerofthetwonumbersshowninmostperiodictables.hydrogenatomsalwayscontain1protoncarbonatomsalwayscontain6protons.Ifthenumberofprotonschanges,thentheatomb
6、ecomesadifferentelement.Theatomicnumber(protonnumber)Whataretheatomic(proton)numbersoftheseelements?1126509tinironsodiumfluorineWhatismassnumber?Electronshaveamassofalmostzero,whichmeansthatthemassofeachatomresultsalmostentirelyfromthenumberofprotonsandneutronsinthenucleus
7、.Thesumoftheprotonsandneutronsinanatom’snucleusisthemassnumber.1413aluminium43lithium01hydrogenneutronsprotonsatomsmass number2771Itisthelargerofthetwonumbersshowninmostperiodictables.massnumber=numberofprotons+numberofneutronsWhat’sthemassnumber?Whatisthemassnumberofthese
8、atoms?322735292259644cobaltcopperheliumNeutronsProtonsAtomsMass numberiodinegermanium5332
