Introductory Chemistry, 2nd Edition Nivaldo Tro.ppt

IntroductoryChemistry,2ndEditionNivaldoTroChapter4AtomsandElements1Tro'sIntroductoryChemistry,Chapter4ExperiencingAtomsAtomsareverysmall;=smallestparticleofanelementthatretainsitscharacteristics2Tro'sIntroductoryChemistry,Chapter4Dalton’posedoftinyindivisibleparticlescalledatomsAllatomsofanelementareidentical;atomsofdifferentelementsaredifferenteverycarbonatomisidenticaltoeveryothercarbonatomtheyhavethesamechemicalandphysicalpropertiesbutcarbonatomsaredifferentfromsulfuratomstheyhavedifferentchemicalandphysicalpropertiesJohnDalton(1766-1844)3Tro'sIntroductoryChemistry,Chapter4Dalton’bineinsimple,whole-positionorDefiniteProportionsChemicalFormulas4Tro'sIntroductoryChemistry,Chapter4Dalton’sAtomicTheoryInchemicalreactions,,justrearrangedtotalmasswillremainthesameLawofConservationofMassatomsofoneelementdonotchangeintoatomsofanotherelementinachemicalreactioncannotturnLeadintoGoldbyachemicalreaction5Tro'sIntroductoryChemistry,Chapter4Dalton’sAtomicTheoryLawofmultipleproportions:pound,binewithmassofA,:CO,();CO2()ThemassofOinCO2istwicethatinCO:=,pounds,bineindifferentratiosorproportions: CO,CO2 ;SO2,SO36Tro'sIntroductoryChemistry,Chapter4ModernEvidenceforAtomsAtomscanbeseenthroughaspecialinstrumentcalledthescanningtunnelingmicroscope(STM)7Tro'sIntroductoryChemistry,poundsandassumedformulas,DaltondeterminedrelativemassesofatomsDaltonbasedhisscaleonH=1amuwenowbaseitonC-12=12amuexactlyunit=atomicmassunit,amu8Tro'sIntroductoryChemistry,Chapter4TheAtomisDivisible!'sIntroductoryChemistry,Chapter4Rutherford’sExperimentLeadBoxRadioactiveSampleGoldFoilFluorescentScreenAlphaParticlesStrikingScreen10Tro'sI