Review1. Determine all possible resonance structures of sulfite.2. Calculate the bond order for s-o. 3. Is there a specific Lewis model that best represents the ion? Use formal charge to support your answer.

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VSEPR&Model&

•  “Valence(Shell(Electron(Pair(Repulsion”(•  Basic(molecular(structure,(builds(upon(Lewis(Model(

•  Attempts(to(account(for(3D(structures(! (e.g(tetrahedral,(seesaw,(octahedral(

•  3D(structures(allow(more(accurate(prediction(of(polarity((remember(how?)(

•  Not(a(quantum(model((no(mention(of(s,(p,(d,(f(orbitals)(

Solution(Chemistry(Notes(

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(((Write(Lewis(diagram(first.(Then(using(the(VSEPR,(make(a(modification(to(the(structure(to(accurately(represent(the(shape.(1. H2O(2. CH4(

3. CO2(4. NH3(

5. CH3OH( 6. BeCl2((Be(eT(def.)(

7. CH3OCH3(8. C6H6(

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2 Bonds

←#*#-o ⇐ a

linear

2 Bonds 3 Bond1 LP ' O

*¥**o ⇐ 3bent trigonal planar

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313 413 5- Bonds OO 240 0 up

g I # equatorial""÷÷¥*¥÷: :÷÷÷*¥¥T ÷: #**Eo⇐slinear T- shape seesaw bi pyramidal

2B 313 413 b-Bonds 6 Bonds4LP - - 3. LP 24

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i! ?;ILP O

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VSEPR&Review&

•  Draw(VSEPR(model(for(each.(Determine(the(molecular(geometry,(electron(geometry,(shape(name,(bond(angle(and(dipole(moment.(! CH4((! NH3(! CO2(! SF4(! CH2O(! ICl5(

H109.50

{ CH4 4+443=8 it It → Hshape w/o LP ⇐ MG =

tetrahedraShape includes ⇐ EG

= tetrahedraltells

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Mq= D pyramid y - HII LEG - tetrahedralHHstsh.tt#tells bond 4

:O :CO2

, SFqCtt20iICl5y0dett@zlH.ao . Sp ②CO2 4+(2-6)=16 : CFE tf 'H

16-4=12 f4 ¢ 0

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Bond 4

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MG - seesaw :¥: SpdECT - O bipyramid

: Hey 900Bond 4=12004900

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Quiz&1&&

•  Drawing(Lewis(diagram(•  Choosing(the(correct(Lewis(diagram(based(on(FC(•  Drawing(VSEPR,(name(of(shape,(bond(angle,(dipole(moment,(polarity,(and(partial(charges(

on Thursday

AP(Chemistry(12(

Bonding((

Valence(Bond(Theory(

Valence&Bond&Theory&

•  Attempts(to(explain(molecular(structure(based(on(quantum(model(•  Results'are'very'similar'to'VSEPR'Model,'and'in'most'cases,'VBT'is'not'needed'to'explain'anything'extra'•  Having(said(that,(the(most(important(contribution(from(VBT(is(hybridisation(

Valence&Bond&Theory&• Recall(that(sVorbital(electrons(and(pVorbital(electrons(have(different(energy(levels((so(do(dVorbital(electrons)(! (For(example,(when(we(write(the(electron(conWiguration(for(C,(we(write(1s22s22p2(

! (The(valence(electrons(in(C(are(the(2s22p2(electrons((4(valence(electrons)(

HpH -&-HpH

O2 2

✓

In CH4 needs sp3x4H

C 15 252 ZPZ µIt -- Tt @DEEfE.H

H

sp ph¥ridH¥### spsspzSp3 It ←core = not used in

bonding

Valence&Bond&Theory&• When(central(atoms(are(bonded,(however,(they(make(bonds(that(are(identical(to(nearby(atoms(•  Problem:(How(can(electrons(of(different(energy(levels(form(bonds(of(identical(energy(level?(•  Solution:'Hybridisation'

Valence&Bond&Theory&

I go"

I 808 88

Hmissing

it-

H sp

spz p

c. sps x

Valence&Bond&Theory&•  Example:(CO2(

! (Carbon(needs(to(make(two'equal'bonds'with(oxygen(

{MG=FG= Linear

2-bonds• op • a d

Q.si#FCFr.Qspzp-71-zs22PZzs#I-1¥If#spx2

2 bonds 3.bonds 4 bonds b-bond

sp sp' Sps sp3d

Hybridisa>on&in&CO2&Ibond

• a o o SigmaO = CFO

( = 152252 zp2° °

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T Et8 bond

⑧y①iI? 2x Zbsopndt b remaininghybrid used pxz

7L indouble2x bond H

Unbybridized lP- orbital t

sp HyobrrbiffiazedI = S bond

= IT bonds µ H