Unit 4 Practice Packet Atomics - · Rutherford bombarded a very thin sheet of gold foil with alpha...

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PracticePacket:Unit4AtomicConcepts

RegentsChemistry:Mr.Palermo

PracticePacketUnit4:Atomics

Vocabulary:_______________Intro________________________Lesson1:__________________Inquiry_____________________Lesson2:__________________Lesson3:__________________Lesson4:__________________Lesson5:__________________Lesson6:__________________Lesson7:__________________

Vocabulary

Foreachword,provideashortbutspecificdefinitionfromYOUROWNBRAIN!Noboringtextbookdefinitions.Writesomethingtohelpyouremembertheword.Explainthewordasifyouwereexplainingittoanelementaryschoolstudent.Giveanexampleifyoucan.Don’tusethewordsgiveninyourdefinition!

Alphaparticle:_______________________________________________________________________________________________________

Anion:_________________________________________________________________________________________________________________

Atom:_________________________________________________________________________________________________________________

AtomicMass:_________________________________________________________________________________________________________

AtomicNumber:_____________________________________________________________________________________________________

Bohr:_________________________________________________________________________________________________________________

BrightLineSpectra:_________________________________________________________________________________________________

Cation:________________________________________________________________________________________________________________

Deflected:_____________________________________________________________________________________________________________

ElectronConfiguration:_____________________________________________________________________________________________

Electron:_____________________________________________________________________________________________________________

ExcitedState:_________________________________________________________________________________________________________

Goldfoilexperiment:________________________________________________________________________________________________

GroundState:_________________________________________________________________________________________________________

Isotope:_______________________________________________________________________________________________________________

MassNumber:_______________________________________________________________________________________________________

Neutron:_____________________________________________________________________________________________________________

Nuclearcharge:______________________________________________________________________________________________________

Nucleus:_____________________________________________________________________________________________________________

Orbital:_______________________________________________________________________________________________________________

Proton:_______________________________________________________________________________________________________________

Rutherford:___________________________________________________________________________________________________________

Thompson:___________________________________________________________________________________________________________

ValenceElectrons:___________________________________________________________________________________________________

WaveMechanicalModel:____________________________________________________________________________________________

IntroductiontoAtomicModels

Background:

Modelsareusedinscienceasawaytorepresentwhatwecannotsee.Theyhelpusworkwith,visualize,andunderstandscientificconcepts. However,modelsareconstantlychangingaswedevelopnewtechnologyandcontinuetomakeadvancements.Wearegoingtostudytheatominthisunit,anditisimportanttolearnabouttheprocessofdevelopingourmostcurrentmodel.

Model1: Dalton

Daltoncameupwiththetheorythatdescribedatomsinfivepostulates,meaning,asetofconceptsortheoriesproposedbyscientists. Daltonusedexperimentationtodevelophispostulatesthroughtestinggases. Hefirstdifferentiatedatomsviaatomicweight.Hisdatawasflawed,however,butheisknownasthefatherofatomictheoryduetohisimmensestridesinthistopic. Hisfivepostulatesarelistedbelow:

i. Allelementsarecomposedoftinyindivisibleparticlescalledatomsthatcannotbebrokendownfurther. *

ii. Atomsofagivenelementareallsimilarintheirphysicalandchemicalproperties. *iii. Atomsofdifferentelementsdifferintheirphysicalandchemicalproperties.iv. Atomsofdifferentelementscombineinsimple,wholenumberratiostoformcompounds.v. Inchemicalreactions,atomsarecombined,separated,orrearranged,butnevercreated,destroyed,or

changed.* ***indicatesthatthepostulatestillholdstruetoday

Dalton’smodelsummarizestheseprinciplesbyshowingthatanatomismadeupofsolid,indivisibleparticles. ThiswasoriginallystatedbyGreekphilosopherDemocritus,andhecalledtheindivisibleparticleatomos(whichmeansindivisible).However,Democritusdidnothaveanysupportforhisclaim.

KeyContentQuestions:

1. EventhoughnewmodelswerediscoveredafterDaltoncreatedhisfiveprinciples,whichoftheseprinciplesstillholdstrue? (actuallywritethemout)

Dalton’smodelof

theatom:

Model2: JJThomson

Usingacathoderaytube,JJThomsondiscoveredtheelectron.Acathoderaytubeis

composedofacathodeornegativeelectrode,andananodeorpositiveelectrodeinsideofanevacuatedglasscontainer. (Electrodesaremetalplateswithpositiveornegativechargesonthesurface).Thomsonappliedachargetothecathoderayandobservedtheflowofelectronsfromcathodetoanodethroughtheopenspaceofthecontainer.Theseobservationschangedthewaythatatomswereportrayedsinceitwasnowdeterminedthatatomscouldbefurtherbrokendown.

Thomson’smodelshowselectronsscatteredthroughoutanatomthatismostlyapositively-chargedcloud.Inadditiontothebeamtravelingfromthenegativecathodetothepositiveanode,Thomsonputamagneticfieldonthetubeandnoticedthebeamwasattractedtothepositiveendofthefield. Thisallowedhimtoconcludetherearenegativelychargedparticlesintheatom.Thomsonalsoconcludedthattheremustbeanopposingpositivechargesurroundingthenegativecharge.

Thomson’s“PlumPudding”Model:

2.WhatdidThomsondeterminethechargeofanelectrontobe?(positiveornegative)

3.Howdidhedeterminethischargebasedonhisexperimentation?

Model3: RutherfordIn1911,themodeloftheatomchangedonceagainafterErnestRutherforddiscoveredthe

nucleus.Rutherfordaimedalphaparticles(positivelychargedparticlesthatrepresentaheliumnucleus)atathinsheetofgoldfoil. BasedonThomson’smodel,heexpectedtheparticlestotravelstraightthroughthefoil. However,thiswasnotthecase.

Rutherfordobservedsomeparticlesthatwentstraightthrough,buthealsonoticedsomedeflectionsbacktowardshimandofftotheside.Thisshowedthatprotonsandelectronswerenotevenlydispersed.Rutherforddeterminedthatprotonsarelocatedinaconcentratedareainthecenterofatom,andtheelectronsaredispersedintheemptyspacearoundit.

ThismeansthatThomson’smodelwasnolongercorrect,andthatprotonswerefoundinadenseareaoftheatomcalledthenucleus.Electrons,ontheotherhand,arefoundintheemptyspacearoundtheatom.

4.WhatdidRutherfordexpecttohappeninhisexperiment?

5.Whatactuallyhappened? Whatdidthismeanaboutthemake-upoftheatom?

6.WhatpartoftheatomisRutherfordcreditedfordiscovering?

Model5:Bohr

In1912,NielsBohrcameupwithatheorythatexplainedwhyelectronsdonotspiralinward(astheyshouldbaseduponclassicalphysicsandparticlemovement).Hestatedthatelectronsfollowtworules.

1. Electronsorbitatspecificdistancesfromthenucleus.Inotherwords,allelectronscanbefoundatacertaindistancefromthenucleusinanorbital.

2. Atomsradiate(giveoff)energywhenanelectronjumpsfromahigher-energyorbittoalower-energyorbit,andabsorbs(takein)energywhentheelectrongetsboostedfromalow-energyorbittoahigh-energyorbit.

Rutherford’sModeloftheatom:

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Thismodelisknownastheplanetarymodelsincetheelectronsareorbitingaroundthenucleusmuchliketheplanetsorbitaroundthesun. Thefirstorbitalonlyholdstwoelectrons.Orbitaltwocanholduptoeightelectrons,orbitalthreecanholduptoeighteenelectrons,andorbitalfourandhighercanholduptothirty-twoelectrons.(2-8-18)

Whatarethecirclesaroundthenucleuscalled?

Whatparticleresidesinthem?

Howcanelectronsmovefromoneorbitaltoanother?

Model6: Today’sModel…QuantumMechanicalModel

Fifteenyearspassedbeforeanothermodeloftheatomwasputintothemix.Thenextmodel,thequantummechanical(electroncloud)model,isamathematicalmodelthatpredictstheprobabilityofelectronlocationsandpathswithinanelectroncloud.ThismodelresultedfromscientistssuchasdeBroglie,Schrödinger,andHeisenberg. Thesescientistsstartedtolookatelectronsactingasbothparticlesandwaves,anddeterminedthattherecanbenocertaintyinfindingthepositionofanelectronifyouknowthemomentumatwhichittravels.Thisledtotheideaofelectronsexistinginanelectroncloudmovingasbothaparticleandawaveatthesametime.Hencecamethequantummechanicalmodel.

Bohr’sModeloftheAtom:

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QuantumMechanicalModel:

IntheQuantumMechanicalmodel,howdoelectronstravel?Wherearetheylocated?

ExtensionQuestion:

Labelthemodels(Dalton,Thomson,Rutherford,Bohr,orQuantumMechanicalmodel).

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LESSON1:ATOMICTHEORY

ObservationofThompson’splumpuddingmodel:Gotohttps://phet.colorado.edu/sims/html/rutherford-scattering/latest/rutherford-scattering_en.htmlandclickonplumpuddingmodel.Clickonthebluebuttononthegunontheleftsidelabeled“alphaparticles.”Observewhatisoccurringandanswerthequestionsbelow.

1. AccordingtowhatyouobservedaboutThompson’splumpuddingmodel,whatwashappeningwiththealphaparticles?

2. Isthismodelaccuratefromwhatyounowknowaboutthestructureoftheatom?ObservationofRutherford’sModel:Gotohttps://phet.colorado.edu/sims/html/rutherford-scattering/latest/rutherford-scattering_en.htmlandclickonRutherfordAtom.Thenclickonthebluebuttononthegunontheleftsidelabeled“alphaparticles.”Observewhatisoccurringandanswerthequestionsbelow.

1. Asthepositivelychargedalphaparticlesareshotatthegoldfoilwhathappenstomostoftheparticlesbaseduponthesimulation?

2. Doallparticlespassrightthroughtheatomsundeflected?

3. Whatcanyouconcludeaboutthechargeofthenucleusfromthesimulation?Whataboutthesize?

Objective:• Describehowthemodernmodeloftheatomhasevolvedoveralongperiodoftimethrough

theworkofmanyscientists• Relateexperimentalevidencetomodelsoftheatom• DescribeindetailRutherford’sExperimentandtheconclusionshemade

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DevelopmentoftheModeloftheAtomUsingyournotes,drawamodelforeachofthefollowing:

Dalton Thompson Rutherford Bohr

1.)J.J.Thomson’sCathodeRayTubeexperimentledtothediscoveryof

1. thepositivelychargedsubatomicparticlecalledtheelectron2. thepositivelychargedsubatomicparticlecalledtheproton3. thepositivelychargedsubatomicparticlecalledtheelectron4. thenegativelychargedsubatomicparticlecalledtheelectron

2.)AccordingtotheBohrModel,

1. electronsarefoundinareasofhighprobabilitycalledorbitals2. electronstravelaroundthenucleusincircularpathscalledorbits3. electronsarefoundinareasofhighprobabilitycalledorbits4. electronstravelaroundthenucleusinrandompathscalledorbitals

3.)AccordingtotheWave-MechanicalModel,

1. electronsarefoundinareasofhighprobabilitycalledorbitals2. electronstravelaroundthenucleusincircularpathscalledorbits3. electronsarefoundinareasofhighprobabilitycalledorbits4. electronstravelaroundthenucleusinrandompathscalledorbitals

4.) In Thomson’s cathode-ray experiment, what evidence led him to believe that the ray consisted of particles, and why did he conclude that the ray was negatively charged?

REGENTSPRACTICE

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5.)Onemodeloftheatomstatesthatatomsaretinyparticlescomposedofauniformmixtureofpositiveandnegativecharges.Scientistsconductedanexperimentwherealphaparticleswereaimedatathinlayerofgoldatoms.Mostofthealphaparticlespasseddirectlythroughthegoldatoms.Afewalphaparticlesweredeflectedfromtheirstraight-linepaths.Anillustrationoftheexperimentisshownbelow.

a. Mostofthealphaparticlespasseddirectlythroughthegoldatomsundisturbed.Whatdoesthisevidencesuggestaboutthestructureofthegoldatoms?

b. Afewofthealphaparticlesweredeflected.Whatdoesthisevidencesuggestaboutthestructureofthegoldatoms

c. Howshouldtheoriginalmodelberevisedbasedontheresultsofthisexperiment?

6.) In1897,J.J.Thomsondemonstratedinanexperimentthatcathoderaysweredeflectedbyanelectricfield.Thissuggested

thatcathoderayswerecomposedofnegativelychargedparticlesfoundinallatoms.Thomsonconcludedthattheatomwasapositivelychargedsphereofalmostuniformdensityinwhichnegativelychargedparticleswereembedded.Thetotalnegativechargeintheatomwasbalancedbythepositivecharge,makingtheatomelectricallyneutral.Intheearly1900s,ErnestRutherfordbombardedaverythinsheetofgoldfoilwithalphaparticles.Afterinterpretingtheresultsofthegoldfoilexperiment,Rutherfordproposedamoresophisticatedmodeloftheatom.

a. StateoneconclusionfromRutherford’sexperimentthatcontradictsoneconclusionmadebyThomson.

b. StateoneaspectofthemodernmodeloftheatomthatagreeswithaconclusionmadebyThomson.

7.)Intermsofelectrons,whatcanweconcludeaboutthecurrentmodeloftheatom?

ASSESSYOURSELFONTHISLESSON:Ifyoumissedanyregentspracticequestionsyoushouldseemeforextrahelpand/orre-watchthelessonvideoassignment

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INQUIRYACTIVITY:BUILDINGANATOM

Go to https://phet.colorado.edu/sims/html/build-an-atom/latest/build-an-atom_en.html and click “atom.”

Build an Atom Before running the simulation, check off “stable” and click the + sign next to mass number and net charge. Then build 3 different examples of atoms that have a stable nucleus and fill in the table below.

Numberofparticlesin

yournucleus:Draw

yournucleusWhatelement

1.Protons:1Neutrons:1

Protons:2Neutrons:2

Protons:3Neutrons:4

1. Which particle (or particles) determines the name of the element you built?

Test your idea by identifying the element for the 3 cases.

Particles ElementSymbol?

MassNumber

WhatParticledeterminestheIdentityofthe

Element?

Nametheelement

1.Protons:6Neutrons:6Electrons:6

�Proton�Neutron�Electron

a. What sub atomic part affects the mass of your atom?

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b. What is a rule for determining the mass? c. Using all of your rules, figure out what changes for each of these actions to an atom. You can test

your ideas with the simulation. If you have new ideas, rewrite your rules.

Start the simulation with 3 protons, 4 neutrons and 3 electrons

Action WhatChanges? HowDoesitaffecttheatom?

AddaProton

�Element

�Charge �Mass

Action WhatChanges? Howdoesitaffecttheatom?

RemoveaNeutron

�Element

�Charge �Mass

RemoveanElectron

�Element �Charge �Mass

AddaElectron

�Element

�Charge �Mass

SubatomicParticles:

SubatomicParticle Charge Mass

Proton

Electron

Neutron

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LESSON2:SUBATOMICPARTICLES

FillinthetablebelowusingtheperiodictableandtableSinyourreferencetable.

Name Symbol Protons Neutrons ElectronsAtomic

Mass#Thisisp+n

Hydrogen 0 1 1

He 2 4

Carbon C 6 12

Nitrogen 7 7 7

Oxygen O 8 8 8

Aluminum 14 13 27

Iron 26 30

Co 27 59

Lithium 4

Beryllium Be 4 4 9

Boron 5 11

Sodium 11 12

Fluorine 9 10

Thetermnuclearchargerepresentsthenumberandsignofthechargeinsidethenucleus.Protonswhichare__________________chargedandneutronswhichare__________________charged,areinthenucleus.Thismeansthenucleusisalways______________charged.The#ofnucleonsisthenumberofparticlesinthenucleus________________________plus_______________________________.

Objective:• Identifythesubatomicparticlesofanatom(proton,neutron,andelectron)• Determinethenumberofprotons,neutrons,electrons,nucleonsandnuclearchargeina

neutral atom

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Completethetablebelow(allareneutral):

1. Thenumberofprotonsinthenucleusof 32Pis:15

(1)15(2)17 (3)32 (4)47

2. Whatisthetotalnumberofelectronsinanatomwithanatomicnumberof13andamassnumberof 27?

(1)13(2)14 (3)27 (4)40

3. Themassnumberofanatomisequaltothetotalnumberofits(1) electronsonly(2)protonsonly(3)electronsandprotons (4)protonsandneutrons

4. Whatisthetotalnumberofneutronsinanatomof39K? 19

(1)1(2)20(3)39(4)58

5. Theatomicnumberofanatomisalwaysequaltothetotalnumberof(1) neutronsinthenucleus (2)protonsinthenucleus(3)neutronsplusprotonsintheatom (4)protonspluselectronsintheatom

Protons Electrons Neutrons Mass#

Atomic#

Nuclearcharge

#ofNucleons

Nucleardiagram

Element’sSymbol

A 44 101 +44 57n44p

B 84 125

C 55 Mn

D 89 227

E 31 +28

F 92 238

REGENTSPRACTICE

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LESSON#3:IONS

Cationsare_____________chargedbecausethey______________________________whenbonding. (positively/negatively) (gain/lose)(electrons/protons)

Anionsare_____________chargedbecausethey______________________________whenbonding. (positively/negatively) (gain/lose)(electrons/protons)

• Ifaparticlehas9protonsand10electrons,whatisthesymbolandcharge?___________• Ifaparticlehas11protonsand10electrons,whatisthesymbolandcharge?___________• Ifaparticlehas12protonsand10electrons,whatisthesymbolandcharge?___________

Giveamathematicalrulefordeterminingthechargeofaparticle:____________________________________

1.Completethefollowingtable

Name Symbol Protons Neutrons Electrons Atomic# Mass#

Copperion

Cu+2 29 35 64

Bariumion

Ba+2 56 137

Goldion

Au+3 118 79

Chlorideion

18 18 17

Fluorideion F- 10

Sulfideion S-2 16

O-2 16

Aluminumion

13 10 27

Objective:• Determinethenumberofprotons,neutrons,andelectronsinanion

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Sinceallatomsstrivetobecomestable(8electronsintheirvalenceshell)whentheygainorloseelectronstoformionstheybecomestable.TheresultingelectronconfigurationoftheionistheSAMEasthatofanoblegas.Forexample,lookattheelectronconfigurationofoxygen.

Theunstableatomofoxygenhasanelectronconfigurationof2-6.

Tobecomestabletheatomgains2valenceelectronsresultingin8valenceelectronsandanelectronconfigurationof2-8whichisthesameconfigurationasthenoblegasNeon.

*****rememberwhenanatomformsanionitdoesn’tbecomeanoblegasitjusthasthesameconfigurationasone.Theprotonandneutronsdonotchangefromatomtoionandthereforewillbedifferentthanthenoblegas.2.CompletethefollowingTable

Ion Charge #ofprotons

#ofelectrons

Electronconfiguration

ElectronConfigurationsameas…

Ionlargerorsmallerthan

atom?Al3+ +3 13 10 2-8 Ne(2-8) smaller

Na+ +1 -2 8

3.Explain,intermsofsubatomicparticles,whyanoxygenatomiselectricallyneutral.

4.Explain,intermsofsubatomicparticles,whyanoxideion,O2-,hasanegativecharge.

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5.Comparethenumberofprotonstothenumberofelectronsinapositiveion.

6.Comparethenumberofprotonstothenumberofelectronsinanegativeion.

7.Explain,intermsofsubatomicparticles,whyachlorineionislargerthanachlorineatom

REGENTSPRACTICE

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LESSON#4:BOHRDIAGRAMS

Bohrdiagramsshowthenumberofprotonsandneutronsinthenucleusandthenumberofelectronsintheirenergylevels.Theelectronconfigurationshowshowmanyelectronsareineachlevelinthegroundstate,orundernormalconditions.

DrawtheBohrdiagramsofthefollowingatoms:Thenon-shadedboxesarepositiveions&theshadedboxesarenegativeions.

K-40 Li-7 Be-9

Cl-35 P-31 S-28

Objective:• ConstructBohrdiagramsforatomsandions

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DrawtheBohrDiagramsforthefollowingions:Thenon-shadedboxesarepositiveions&theshadedboxesarenegativeions.

K+1 Li+1 Be+2

Cl-1 P-3 S-2

1. DrawtheBohrdiagramforBandMg+32. Whenanatomformsapositiveion,doesthesizegetlargerorsmaller?Explain.

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3. DrawtheBohrdiagramforSandS-24. Whenanatomformsanegativeion,doesthesizegetlargerorsmaller?Explain.

REGENTSPRACTICE

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LESSON#5:ISOTOPESANDAVERAGEATOMICMASSIntermsofsubatomicparticles,isotopesareatomsofthesameelement,whichhaveadifferentnumberof___________________butthesamenumberof________________.Thusthe___________________numberisthesamebutthe______________numberisdifferent.Isotopenamescanbefollowedbythemassnumber.Example:Carbon-14andCarbon-12.Isotopesymbolsincludetheelement’ssymbolwiththemassnumberonthetopleftandtheatomicnumberonthebottomleft.Example:146Cand126C

Name IsotopeSymbol

AtomicMass

AtomicNumber Neutrons Protons Electrons Nuclear

ChargeLithium-6

Lithium-7

Boron-10

Boron-11

Sodium-22

Sodium-24

Aluminum-26

Aluminum-27

Iron-55

Iron-56

Zinc-65

Zinc-66

Foreachpairabove,lookuptheelement’satomicmassfromthereferencetableanddecidewhichisotopeismoreabundant.Circlethemoreabundantisotope’sname.

Objective:• Differentiatebetweenatomicnumber,massnumber,and(average)atomicmass• Calculatethe(average)atomicmassforallisotopesofanelement• Calculatethenumberofneutronsinanisotope

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Calculatingaverageatomicmass

1. Whatisyourquartergradeifyourcategorieshavethefollowingweights?YourGrades:

Test(60%oftheaverageofalltestsscores) 60Labs(15%oftheaverageofalllabscores) 90Quiz(25%oftheaverageofallhw/cw) 95

Findtheaverageatomicmassforeachofthefollowing:(showyourwork)

2. Silver:55.0%Ag-107,45.0%Ag-109

3. Indium:40.0%In-113,60.0%In-115

4. Rhendium:30.0%Re-185,70%Re-187

5. Copper:75.0%Cu-63,25.0%Cu-65

6. Chlorine:75.5%Cl-35,therestCl-37

7. Oxygen:99.76%O-16,0.046%O-17,and0.20%O-18

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4. Baseyouranswerstothefollowingquestionsonthedatatablebelow,whichshowsthreeisotopesofneon.

a. Intermsofatomicparticles,stateonedifferencebetweenthesethreeisotopesofneon.

b. Basedontheatomicmassesandthenaturalabundancesshowninthedatatable,showacorrectnumericalsetupforcalculatingtheaverageatomicmassofneon.

c. Basedonnaturalabundances,theaverageatomicmassofneonisclosesttowhichwholenumber?

REGENTSPRACTICE

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5. TheatomicmassofelementAis63.6atomicmassunits.TheonlynaturallyoccurringisotopesofelementAareA-63andA-65.ThepercentabundancesinanaturallyoccurringsampleofelementAareclosestto(1)31%A-63and69%A-65 (2)50%A-63and50%A-65(3)69%A-63and31%A-65 (4)100%A-63and0%A-65

6. WhatisthemostabundantorcommonisotopeofVanadium(V)?

a)50V b)52V c)51V d)49V

7. A100.00-gramsampleofnaturallyoccurringboroncontains19.78gramsofboron-10(atomicmass=10.01atomicmassunits)and80.22gramsofboron-11(atomicmass=11.01atomicmassunits).Whichnumericalsetupcanbeusedtodeterminetheatomicmassofnaturallyoccurringboron?

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LESSON#6GROUNDVS.EXCITEDSTATEANDBRIGHTLINESPECTRUM

1. Completethetablebelow.Thefirstoneisdoneforyou.

Electronconfiguration

Total#ofe-‘s

Total#of

e-shells

e-shellwiththehighestenergye-‘s

Excited-orground-state

Atom’ssymbol

AtomA 2-8-4 14 3 3rd ground SiAtomB 2-3-1 AtomC 2-8-7-1 AtomD 2-8-18-6 AtomE 2-8-18-17-5 AtomF 1-7

2. Completethetablebelow.Thefirstoneisdoneforyou.

Elementsymbol

Elementname

Ground-stateelectronconfiguration

#ofvalenceelectrons

Giveanexampleofanexcited-stateelectron

configurationO oxygen 2-6 6 2-5-1Mg He K N P F Sr Al Br Cu

Objective:• Differentiatebetweenexcitedandgroundstate• Explainhowlightisproduced• Identifysubstancesbasedupontheirbrightlinespectra

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3. DrawaBohrmodelforSodiuminthegroundstate.Indicatewithanarrowwhatdirectionanelectronmoveswhenenergyisabsorbed.

4. Onthesamemodelabove,drawanarrowtoindicatewhatdirectionanelectronmoveswhenenergyisreleased.Whattypeofenergyisreleased?

5. Baseyouranswerstoquestions4and5onthediagrambelow,whichshowsbright-linespectraofselectedelements.

6. Identifythetwoelementsintheunknownspectrum._________________________________

7. Explainhowabright-linespectrumisproduced,intermsofelectronsandenergystates.

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REGENTSPRACTICE

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LESSON#7LEWISDOTDIAGRAMS

Lewisdiagramsshowonlytheatom’ssymbolanddotsrepresentingthevalenceelectrons.Themostvalenceelectronsanatomcanhaveis____sothemostdotsyouwilldrawis____.Pleasemakedotsveryvisible!

Examplesofatoms:

Name Protons Neutrons ElectronsElectron

Configuration

Valence

ElectronsLewisDiagram

Rubidium-85

Barium-138

Strontium-88

Bromine-80

Oxygen-16

Nitrogen-14

Objective:• ConstructLewisdotdiagramsforatomsandions

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ExamplesofIons:

Name Protons Neutrons Electrons ElectronConfiguration

ValenceElectrons

LewisDiagram

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REGENTSPRACTICE

Unit 4 Practice Packet Atomics - · Rutherford bombarded a very thin sheet of gold foil with alpha...

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