WPC< >'"0"$v[T6{'̃a4/mSo;Q``?ՅEq9#q(&hOk1Z1hœ$k =k&pmP\ͣ3.ѽJut6p,?9ơ0i&"&ȆF׀Jkv 3ȲOwcVц?4h0˜ku Q Itżݍ2> &VĒPABf:Y0Hf$fH"ykU9 p%MzEǏ LU:- ws$|EUlngC nֵ!D+)Q-bD7C. >aTa{A,$%'_XNUeR+s(*HO:Uјz}Ub9Z2'ѵxL`^5]Huڄ>et2l(6˗aOEU7ʥRU>| 0F 0,@ 07 0. 0" 0 0 0 0 0 0 0 0 0h 0J 0) 0 0 0 0 0 0o 0P 01 0 0 0 0a!U:# 0># 0 % 0$& 0@' 0:() 0$b* 0*+ 0<, 0', 0. 0/ 0 k1 0u2 0= 4 1U5 7 s5UD,5 1g5 76 1U 6 7 u6f6a6 B5*6f6a6f6a6f6a6 1g7 7j7 1ex7 77 B78 08#8UN: %:M:(:N!; 1u#; 72;^ ;w;4;; m;\  `&Times New Roman' CHAPTER 4: CHEMICAL BONDING susie0Giordano .   2P+M 0_level1  , 8.4 <DL!823  ..  5+ 4 <DL!5  2M+M 0_level2  X 5+4 44 <DL!523  ..  5+ 4 <DL!5  2M+M 0_level3   5+` ` ` <DL!523  ..  5+ 4 <DL!5  2J+M 0_level4   2( <DL!223  ..  5+ 4 <DL!5  2J+M 0_level5   2( <DL!223  ..  5+ 4 <DL!5  2G+M 0_level6   /% <DL!/23  ..  5+ 4 <DL!5  2G+M 0_level7  4 /% <DL!/23  ..  5+ 4 <DL!5  2D+M 0_level8  ` ,"< <<DL!,23  ..  5+ 4 <DL!5  2D+M 0_level9   ,"h hhDL!,23  ..  5+ 4 <DL!5  2PM 0_levsl1  , 8.4 <DL!823  Ԁ  5+ 4 <DL!5  2MM 0_levsl2  X 5+4 44 <DL!523  Ԁ  5+ 4 <DL!5  2MM 0_levsl3   5+` ` ` <DL!523  Ԁ  5+ 4 <DL!5  2JM 0_levsl4   2( <DL!223  Ԁ  5+ 4 <DL!5  2JM 0_levsl5   2( <DL!223  Ԁ  5+ 4 <DL!5  2GM 0_levsl6   /% <DL!/23  Ԁ  5+ 4 <DL!5  2GM 0_levsl7  4 /% <DL!/23  Ԁ  5+ 4 <DL!5  2DM 0_levsl8  ` ,"< <<DL!,23  Ԁ  5+ 4 <DL!5  2DM 0_levsl9   ,"h hhDL!,23  Ԁ  5+ 4 <DL!5  2PM 0_levnl1  , 8.4 <DL!823   5+ 4 <DL!5  2MM 0_levnl2  X 5+4 44 <DL!523   5+ 4 <DL!5  2MM 0_levnl3   5+` ` ` <DL!523   5+ 4 <DL!5  2JM 0_levnl4   2( <DL!223   5+ 4 <DL!5  2JM 0_levnl5   2( <DL!223   5+ 4 <DL!5  2GM 0_levnl6   /% <DL!/23   5+ 4 <DL!5  2GM 0_levnl7  4 /% <DL!/23   5+ 4 <DL!5  2DM 0_levnl8  ` ,"< <<DL!,23   5+ 4 <DL!5  2DM 0_levnl9   ,"h hhDL!,23   5+ 4 <DL!5  6 4Heading 1 CE O* `"Comic Sans MSO       XXXS\  `&Times New RomanS  CE * `"Comic Sans MS6 4Heading 2O* `"Comic Sans MSO     5+` ` ` <DL!5      5+ 4 <DL!5XXXS\  `&Times New RomanS 6 4Heading 3  O* `"Comic Sans MSO r 2(N N N <DL!2    5+ 4 <DL!5XXXS\  `&Times New RomanS  6u l4Heading 4O* `"Comic Sans MSO   XXXS\  `&Times New RomanS6 z4Heading 5O* `"Comic Sans MSO       XXXS\  `&Times New RomanS 6 w4Heading 6O* `"Comic Sans MSO      XXXS\  `&Times New RomanS6u l4Heading 7O* `"Comic Sans MSO   XXXS\  `&Times New RomanS6x o4Heading 8O* `"Comic Sans MSO   XXXS\  `&Times New RomanS <:Default Para.|} ,TitleO* `"Comic Sans MSO     XXXS\  `&Times New RomanS < :Body Text I1O* `"Comic Sans MSO ,   8.4 <DL!8    5+ 4 <DL!5XXXS\  `&Times New RomanS < :Body Text In  O* `"Comic Sans MSO r 2(N N N <DL!2  5+ 4 <DL!5XXXS\  `&Times New RomanS  6hl 4Body TextO* `"Comic Sans MSOXXXS\  `&Times New RomanS< :Body Text I2O* `"Comic Sans MSO , 8.4 <DL!8  5+ 4 <DL!5XXXS\  `&Times New RomanS:ko 8Body Text 2O* `"Comic Sans MSO XXXS\  `&Times New RomanS  359=AEIMQ1 o o o. (\ Y`Symbol 35=CIOU[a2(i)1.i.1.a.i.1.a.1 i. 359=AEIMQ3 - o o3 Table_A& d dTable_BTable_CTable_D 35=CIOU[a4(1)a.i.1.a.i.1.a.> i. 35;AGMSY_51.a.i.1.a.i.1.a.@ i. d#|x($..      CEUS.,FXoXXFXXoXXFXoLexmark 3200 Series ColorFinePX,,,,PX0(9 Z6Times New Roman RegularFX3#37=CIQYag1.a.i.(1)(a)(i)1)a)Ki)7N- TI-+00U D!..      CEUS.,FXoXXFXXoXXFXo  _       W(BAXXo6BA     (   CHAPTER4:CHEMICALBONDING( v݌  Ќ  X=X6XoXXX=     BAXXo6BA  . (03K ""  ,B.4 <DL!XB  X,  E(4 4 <DL!4X!E062 3   4   60Ofthemorethanonehundredelementsthatoccurin   natureorthathavebeenproducedsynthetically,onlythe R noblegasesexistnaturallyassingle,uncombinedatoms.݌  Ќ X! X44X!!   ""  ,B.4 <DL!XB  X,E(4 4 <DL!4X!E062 3   4   60Theatomsofallotherelementsoccurinsomecombined  Y form,bondedtogether.݌ !  Ќ X! X44X!!    ` 6"< <<DL!X6 CHEMICALBONDS: electrostaticforcesthatholdatoms  (  togetherincompounds. m    ` E+ 4 <DL!<<<X!ECECE.,6666      &  4   CHAPTER4.1:LEWISTHEORYOFBONDING4   Ԍ   Ќ  6666 CE.,CE.,  ' / /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06 2 3   4   60EdwardFrankland(1852)statedthateachelementhasa P fixedvalencethatdeterminesitsbondingcapacity.  ݌  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06` 2 3   4   60FriedrichKekuleillustratedabondasadashbetween ] bondingatomswhichwenowcallstructuraldiagrams(fig.1  pg.224)` `݌ d Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E062 3   4   60ThestorystartswithRichardAbegg(1904),wherehe , suggestedthatthe stabilityofthe inert(noble)gaswas q duetothenumberofoutermostelectrons.݌  3 Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E062 3   4   60Duetogainingorlosingelectrons,theionswould,inturn,be !x heldtogetherbyelectrostaticcharges,resultinginan ionic @# bond withinacrystalofsalt.݌ $! Ќ X$ X!44X!$   ̀EG.Na+Cl06_ _60ԀNa+󀀀+Cl󀀀06_ _60Ԁ_NaCl_Ԁ '# ̀Sodium+Chlorine06_ _60ԀSodiumChloride )&  ,E.4 <DL!X!E /o,# _Whydoatomsformbondsatall?  Theanswertothisquestioninvolves energy. Innature,   systemsoflowerenergytendtobefavouredoversystemsof R higherenergy.Inotherwords, lowerenergysystemstendto  haveagreaterstabilitythanhigherenergysystems.   Y Bondedatoms,therefore,tendtohavelowerenergythan !  single,uncombinedatoms. f  )6666 ,,  K.4 <DL!4X!K  )  USINGLEWISSTRUCTURESTOREPRESENTATOMSIN z  CHEMICALBONDING)V݌ <  Ќ ,,  04X!4X!06666  K.4 <DL!4X!K / /""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E06 2 3   `   60Chemicalbondinginvolvestheinteractionofvalence P electronstheelectronsthatoccupytheoutermost  principalenergylevelofanatom. ݌ ] Ќ ,-4X!` ` X!-   ""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E062 3   `   60ReadoverthekeyideasoftheLewisTheoryofbonding  (page224)݌ d Ќ ,-4X!` ` X!-   ""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E06 2 3   `   60WriteouttheRulesforDrawingLewisStructureson , page225. !݌ q Ќ ,-4X!` ` X!-   ""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E06/#2 3   `   60DrawingaLewisstructureforamoleculeletsyousee  3 exactlyhowmanyelectronsareinvolvedineachbond,and !x helpsyoutokeeptrackofthenumberofvalence @# electrons./#5$݌ $! Ќ ,-4X!` ` X!-   ""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E06&2 3   `   60Therearetwowaystoshowthebondingpairsof %G" electrons:(i)usedotsonly& '݌ '# Ќ ,-4X!` ` X!-   X,H+4 44 <DL!4X!HӀ(ii)uselinesbetweenatoms T($ / /""  ,XH.4 <DL!444X!H  ,B% <DL!4X!B06)2 3     60Dotsarereservedforrepresentinga lonepair (anon )& bondingpair)ofelectrons.)*݌ *[' Ќ X'444X!  X!'   XE+` ` ` <DL!444X!EN 6OCO or 󀀀OCO .*+" Ѐ  Ѐ(fourlonepairs) & 6 N""  ,K.4 <DL!` ` ` X!K  ,B% <DL!4X!B06,2 3     60Recall:Chemistsclassifysubstancesaccordingto S  theirbondsandtheforcesofattractionthatexist   betweentheirparticles.,-݌  Z Ќ *` ` ` X!  X!*   ""  ,K.4 <DL!` ` ` X!K  ,B% <DL!4X!B06f/2 3     60Readpages226227:LewisStructuresandQuantum "  Mechanicsf/i0݌ g  Ќ *` ` ` X!  X!*   ""  ,K.4 <DL!` ` ` X!K  ,B% <DL!4X!B0612 3     60Dothefollowingquestionspage227#1!5,6,812݌ )  Ќ *` ` ` X!  X!*   H+` ` ` <DL!` ` ` X!H N 6N  N    H+` ` ` <DL!` ` ` X!H    & F  4  TYPESOFCHEMICALBONDS 44 4Ԍ =  Ќ   0` ` ` X!` ` ` X!06 N66   H+` ` ` <DL!` ` ` X!HN 6'F4 1 (00. / /""  ,K.4 <DL!` ` ` X!K  | ,?" <DL!4X!?  N 72(  i  )3     IONICBOND 7*8݌ & Ќ *` ` ` X!  X!* |  ""  ,K.4 <DL!` ` ` X!K  | ,?" <DL!4X!? 92(  ii  )3     COVALENTBOND 9:݌  Ќ *` ` ` X!  X!* |  ""  ,K.4 <DL!` ` ` X!K  | ,?" <DL!4X!? :2(  iii  )3     METALLICBOND:;݌   Ќ *` ` ` X!  X!* |  H+ 4 <DL!` ` ` X!HIONICBOND:  e 6  . (001 / / ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06>2 3   4   60The transfer ofelectronsbetweenametaltoanonmetal. >?݌ #  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E068@2 3   4   60Theforceofattractionbetweenoppositelychargedions $b! (cationsandanions). 8@8A݌ *&" Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06~B2 3   4   60Ionicbondingoccursbetweenatomsofelementsthathave o'# largedifferencesinelectronegativityusuallyametalwitha (1% verylowelectronegativityandanonmetalwithaveryhigh )v& electronegativity. ~B~C݌ >+' Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06gE2 3   4   60Directheatingofthecrystalsaltscannotseparatethe ,) unitsofioniccompoundssuchassodiumchlorideand -E* magnesiumfluorideeasily. gEgF݌  /+  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06G2 3   4   60Theionsthatmakeuptheionicsolidarearrangedina  specificarrayofrepeatingunits. GH݌ E Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06NJ2 3   4   60Insolidsodiumchloride,forexample,theionsarearranged   inarigidlatticestructure. NJNK݌ R Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06L2 3   4   60Insuchsystems,thecationsandanionsarearrangedso  thatthesystemhastheminimumpossibleenergy. LM݌  Y Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06O2 3   4   60Becauseofthelargedifferencesinelectronegativity,the !  atomsinanioniccompoundusuallycomefromthesblock f  metalsandthepblocknonmetals. OP݌  (  Ќ X$ X!44X!$   ,E.4 <DL!X!E* 6666 r,E(N N N <DL!4X!E  *Q  Questions:Illustrate(usingorbitaldiagramsandLewis z  Ѐstructures)theformationofMagnesiumfluoride.*QR݌ <  Ќ ,r04X!N N N X!06666    r,E(N N N <DL!4X!E   ЀSolution: I    Ѐ AnorbitaldiagramforMgF2 P    FF ]    e  '  l  4  MgMg2+ y!  ";  #  $C!   &" FF P'#  (%  X)%  ALewisStructureForMgF2 *'    +_(!  ,")"  -g*#  //+$ Ї  N 6ԀF E ! N  NN  N rrE(N N N <DL!N N N X!E    & F !W  Mg+02 N N 02Ԁ[F][Mg][F]!WX  (001 / /""  ,E.4 <DL!X!E   ,E(` ` <DL!4X!Ey2(  1  )3   `   SinceHisalwaysplacedattheendpositionandCisless I electronegativethanO,Cshouldbethecentralatom.   PlacetheotheratomsaroundC,attachedbythesingle P bonds.yh݌  Ќ ' X!` ` X!'   ""  ,E.4 <DL!X!E   ,E(` ` <DL!4X!E22(  2  )3   `   Determinethetotalnumberofvalenceatoms:2!݌ $! Ќ ' X!` ` X!'   ,E.4 <DL!X!È(1CatomX4e/Catom)+(1OatomX6e/Oatom)+ '# Ѐ(2HatomsX1e/Hatom) T($ ̀=4e+6e+2e *[' ̀=12e h-)!  /o,# Then,determinethetotalnumberofelectronsrequiredfor  eachatominthestructuretoachieveanoblegas E configuration.Thiswouldbe8eforCand8eforO(tofill   theirrespectivevalenceenergylevels)and2eforeachH(to R fillits1sorbital).SothetotalnumberforCH2Ois:  (2atomsX8e/atom)+(2atomsX2e/atom) !  =20e  (  Tofindthenumberofsharedelectrons,subtractthefirst 5  totalfromthesecond. z  20e12e=8e   Nowdividethenumberofsharedelectronsbythetwoto   obtainthenumberofbonds. P 20e12e=8e06 60Ԁ2=4covalentbonds ] Sincethereareonlythreeatomssurroundingthecentral d atom,youcaninferthatoneofthebondsislikelyadouble , bond. q ""  ,,K.4 <DL!4X!K   ,E(` ` <DL!4X!E2(  3  )3   `   Determinethenumberofnonbondingelectronsby @# subtractingthenumberofsharedelectronsfromthe $! totalnumberofvalenceelectrons.݌ %G" Ќ ,-4X!` ` X!-   ,H+ 4 <DL!4X!H B+` ` ` <DL!X!B12valenceelectrons8sharedelectrons T($ =4nonbondingvalenceelectrons(thatis,2lonepairs) *[' SinceHcanonlyformasinglebond,apossiblestructure .*+" is: /o,# ЇCheckyoursolution: z  Eachatomhasachievedanoblegasconfiguration.Thus,   youcanbeconfidentthatthisisareasonableLewis I structure.    ,K.4 <DL!` ` ` X!K̀   ,H+ 4 <DL!4X!H COORDINATECOVALENTBONDS:   3 Youknowthatacovalentbondinvolvesthesharingofapairof $! electronsbetweentwoatoms;eachatomcontributesoneelectron %G" tothesharedpair.Insomecases,suchasthehydroniumion, '# H30+,oneatomcontributesbothoftheelectronstotheshared T($ pair.Thebondinthesecasesiscalleda coordinatecovalent )& bond .Intermsofthequantummechanicalmodel,acoordinate *[' covalentbondformswhenafilledatomicorbitaloverlapswithan #,(  emptyatomicorbital.Onceacoordinatecovalentbondis h-)! formed,itbehavesinthesamewayasanyothersinglecovalent .*+" bond. /o,# ЇPRACTICEPROBLEM: E DrawtheLewisstructurefortheammoniumion,NH4+. R SOLUTION: !  Theformula,NH4+,tellsyouthenumberofeachkindofatomin  (  theion. m  SinceHisalwaysplacedattheendposition,Nisthecentral z  atom. <  Totalnumberofvalenceelectrons: , (1NatomX5e/Natom)+(4HatomsX1e/Hatom)1e  3 =8e @# Totalnumberofelectronsrequiredfornoblegasconfiguration: %G" (1atomX8e/atom)+(4atomsX2e/atom) T($ =16e *[' Numberofsharedelectrons,andtheresultingnumberofbonds: .*+"  /o,# 16e!8e=8e  8e06 60Ԁ2=4covalentbonds   Numberofnonbondingelectrons:  8valenceelectrons8sharedelectrons !  =0nonbondingelectrons(0lonepairs)  (  ApossiblestructureforNH4+is: 5   Note: TheLewisstructureforammoniumdoesnotindicatewhich d atomprovideseachsharedpairofelectronsaroundthecentral , nitrogenatom.However,thequantummechanicalmodelofthe q atomcanexplainthebondingaroundthisnitrogenatom.The  3 condensedelectronconfigurationfornitrogenis[Ne]2s22p3. !x Eachnitrogenatomhasonlythreeunpaired2pelectronsinthree @# halffilledorbitalsavailableforbonding.Sincetherearefour $! covalentbondsshownaroundnitrogenintheLewisstructure, %G" electronsinoneofthebondsmusthavecomefromthefilled '# orbitalsofnitrogen.Therefore,oneofthebondsaroundthe T($ centralnitrogenatommustbeacoordinatecovalentbond. )&  /o,# -6666   -  RESONANCESTRUCTURES:MORETHANONEPOSSIBLE  LEWISSTRUCTURE-݌ E Ќ6666  -6666   -  -A݌̌6666  -6666   -  -"݌̌6666  -6666   -  LewisstructureofCHO2:-݌  Ќ6666  -6666   -  -݌̌6666  -6666   -  -݌̌6666  -6666   -  -݌̌6666  -6666   -e  -e݌̌6666  -6666   -F  -F݌̌6666  -6666   -'  -'݌̌6666  -6666   -  -d݌̌6666  -6666   -  -E݌̌6666  -6666   -  -&݌̌6666  -6666   -  -݌̌6666  -6666   -  -݌̌6666  -6666   -m  -m݌̌6666  -6666   -N  -N݌̌6666  -6666   -/  -/݌̌6666   . (00> / /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E062 3   4   60ExperimentaldatashowsCObondsareidentical(between  expectedvaluesfordoubleandsinglebonds)݌ d Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E062 3   4   60ThereforeLewisstructurefails݌ , Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E062 3   4   60UseResonanceStructures݌ q Ќ X$ X!44X!$   ResonanceStructures: aremodelsthatgivethesamerelative !x positionofatomsasinLewisstructures,butshowdifferent @# placesfortheirbondingandlonepairs. $!  /o,# Ї/ /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06E 2 3   4   60Theactualstructureisaresonance hybrid ofthetwo  Y resonancestructures.E E ݌ !  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06 2 3   4   60Thestructuredoes not flipflopbetweenthesetwo f  structures.  ݌  (  Ќ X$ X!44X!$   &6666    &  &   Anotherexample:NO3& :  Ԍ z  Ќ6666  'z. +6666  +)  PracticeProblem:+)݌  Ќ6666   @ (00. / /""  ,E.4 <DL!X!E   ,E(  <DL!4X!E2  1  .3      DrawLewisstructuresforeachofthefollowingmolecules:݌ d Ќ ' X! X!'   B+  <DL!X!B(a)NH3󀀀(b)CF4󀀀(c)H2S(d)ClNO , ""  ,K.4 <DL! X!K   ,E(  <DL!4X!E2  2  .3      DrawLewisstructuresforeachofthefollowingions !x (considerresonancestructures).݌ @# Ќ - X! X!-   ,K.4 <DL! X!K ,H+  <DL!4X!H(a)ClO3󀀀(b)SO32󀀀(c)CO32 %G"  H+ 4 <DL! X!H 򀀀 3.DrawaLewisstructureforN2H4. )&  -6666  -  CENTRALATOMSWITHANEXPANDEDVALENCELEVEL:-݌ /o,# Ќ6666   . (00@ / /""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06s2 3   4   60Theoctetruleallowsamaximumoffourbonds(eight   electrons)toformaroundanatom.ss݌ R Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E062 3   4   60Baseduponenergies,however,chemistshavesuggested  thatthebondinginsomemolecules(andpolyatomicions)are  Y bestexplainedbyamodelthatshowsmorethaneight !  electronsinthevalenceenergylevelofthecentralatom.݌ f  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E062 3   4   60Thiscentralatomissaidtohavean expandedvalence  (  energylevel. ݌ m  Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E06 2 3   4   60Elementsofthethirdrow(andsubsequentrows)areableto 5  putmorethan8electronsintheirvalenceshell. !݌ z  Ќ X$ X!44X!$   ,E.4 <DL!X!E Why????    / /""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E06#2 3   `   60Itisbelievedthattheyareabletousetheir   unfilled/emptydorbitals.#%݌ P Ќ ,-4X!` ` X!-   ""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E06G&2 3   `   60Untilrecently,chemistsexplainedbondinginmolecules  suchasPCl5usingthisideaabove.G&M'݌ ] Ќ ,-4X!` ` X!-   ""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E06(2 3   `   60However,experimentalevidencedoesnotsupportthis  idea.()݌ d Ќ ,-4X!` ` X!-   ""  ,,K.4 <DL!4X!K  ,E(` ` <DL!4X!E06*2 3   `   60Currentthinkingsuggeststhatlargeratomscan , accommodateadditionalvalenceelectronsbecauseof q theirsize.*+݌  3 Ќ ,-4X!` ` X!-   ,H+ 4 <DL!4X!HOneexamplewithanexpandedvalenceenergylevelis @# phosphorouspentachloride,PCl5.Thissubstanceisusedin $! agricultural,pharmaceutical,anddyeingindustries.Organic %G" chemistsalsousereactionswithPCl5toidentifycompoundsthat '# containhydroxylgroups. T($  XB+4 44 <DL!X!B XE+ 4 <DL!444X!E /o,# Ї&6666    &  &0  EXCEPTIONSTOTHERULES!!&0}0 -Y0Ԍ   Ќ6666  'q0/ / ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E0612 3   4   60UseLewisstructurestomakepredictionsaboutmolecular   shape(discussedlater).12݌ P Ќ X$ X!44X!$   ""  ,E.4 <DL!X!E  X,E(4 4 <DL!4X!E0632 3   4   60Octetrulesnotalwaysfollowed:eg.Expandedoctet34݌  Ќ X$ X!44X!$   ,E.4 <DL!X!E""  ,,K.4 <DL!4X!K  X,E(4 4 <DL!4X!E06C62 3   4   60Elementsinthethirdrowofhigherhaveroominvalence )& shellformorethan8electronsC6I7݌ *[' Ќ ,X*4X!44X!*   K.4 <DL!4X!KEg.Incompleteoctet .*+"  /o,# Ї-6666   ,-39  RULESFORDRAWINGELECTRONDOTDIAGRAMSOF z  MORECOMPLEXMOLECULES:-399݌ <  Ќ6666   @ (00. / /""  ,K.4 <DL!4X!K   ,E(r r <DL!4X!E>;2  1  .3   r   Identifythecentralatomleastelectronegativeisthe   centralatomexcepthydrogen.>;3<݌ P Ќ -4X!rr X!-   ""  ,K.4 <DL!4X!K   ,E(r r <DL!4X!Ex=2  2  .3   r   Drawelectrondotformula.x=m>݌  Ќ -4X!rr X!-   ""  ,K.4 <DL!4X!K   ,E(r r <DL!4X!Ec?2  3  .3   r   Determinethenumberofbondsby:c?X@݌ ] Ќ -4X!rr X!-   K.4 <DL!4X!K  V3222L!4X!3#bonds=totalelectronsneeded#ofelectrons , Ѐavailable q Ѐ____________________________________  3  !x ЀN 62 @# 6 N $`!  (&"  m'# Eg.SO42,H2SO4 (/%  )t&  *7'   VH+ 4 <DL!222X!HX=X6XoXXX=