1-Orbitals Notes in Class 09-03-13
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Transcript of 1-Orbitals Notes in Class 09-03-13
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8/13/2019 1-Orbitals Notes in Class 09-03-13
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Laterinthesemester,we
willbestudyingbim
olecularsubstitution
reactio
ns.Inthereactionshownbelow,thestrongbaseHOwillreact
withan
emptyorbitalofth
eC-Brbond.What
doesthisorbitalloo
klike?
Fromw
hichdirectiondoy
outhinktheHOwillreactwiththeC-B
r
bond?
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Topic1
OrbitalsandBo
nding
Stru
ctureoforganicmolecules
1)W
herearethe
electronsinabond?
2)I
felectronsareaddedtoa
molecule/bondwherewill
t
heygo?
3)H
owarebonds
arrangedaro
undanatominamolecule?
Toanswerthesequestions:
1)
AtomicStructurea
ndorbitals
2)HybridOrbitals
3)CovalentBonds
4)Molec
ularorbitaltheory
5)Electronegativity
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A
tomicO
rbitals
Atomic
orbitals(AOs)describethestateofelectronsa
boutanatom:
Energy
S
patialdistributio
n
Correlationwitha
notherelectron(i.e.,occupancy
empty,half-
filled,filled)
1s
2s
2px
2py
2pz
Atomicorbitalsarede
terminedby4quantumnumbers:
n-principalquantumn
umber;l-relate
dtoshape
m
-relatedtoorienta
tion;s-spin
n=1,l=0
m=0,s=1/2
n=2,l=0
m=0,s=1/2
n=2,l=1
m=-1,s=1/2
n=2,l=1
m=-0,s=1/2
n=2,l=1
m=+1,s=1/2
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A
tomicOrbitals
1s
2s
2px
2py
2pz
The(+)or()signsind
icatethemathe
maticalsignsoftheequations.
An
odeisthepoint/surfaceatwhichoppositesignsofthewave
functionareseparated.Theprobabil
ityoffindingan
electronata
nodeiszero.
Thesignsoftheorbi
tallobescanalsoberepresented
byshading.
1s
2
s
Energy
1s
2s
2pxyz
2px
2
py
2pz
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T
he2pOrbitals
Noticethattheporbitalsare0atthe
originandchangesignthis
iscalled
anode.Whathappenswhena
positiveandnegativewave
interact?
a.Theymo
vetowardsea
chotherbeca
usepositive
andnegativechargesattracteachoth
er.
b.Theycanceleachothe
rout
x
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Electronegativityincreasestot
herightandu
p
TheOctet
Rule
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Molec
ularOrbitalTheor
y
M
olecularorbital
describeselectr
ondensityonmo
lecule
C
anbeapproximatedasalinearco
mbinationofato
micorbitals
(LC
AO)
N
umberofatomic
orbitals=numb
erofmolecularorbitals
M
olecularOrbitalsofH2
Bond
ingmolecularor
bital-electrons
concentratedbe
tweennuclei
andshieldnucleifromeachother
Antib
ondingmolecularorbital-noelectrondensitybetweennuclei
-nucleirepeleachother.
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Behavioro
fWave
s
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Molecu
larOrbitalTheory
-H2
BondingMolecularOrbital
AntibondingMolec
ularOrbital
Const
ructiveInterfer
ence
DestructiveInterference
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M
olecular
OrbitalsMethane
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2s
2px
2py2pz
StartingAOs
sphybrid
sp2hybrid
sp3hybrid
Hybrid
orbitals
haved
ifferent
sp
atial
arrangements.
splinear
sp2
trigonalplanar
sp3
tetrahedral
sp
sp
2p
2pz
sp2
sp2
sp22py
sp3
sp3sp3sp3
C H
H
H
H
1
09.5
120
180
H
ybridOrbitals
Non-bonding
Non-bonding
Be-1s22s2
H-1s1
B-1s22s22p1
H-1s1
C-1s22s22p2
H-1s1
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sp2hybrid
sp2
trigonalplan
ar
sp2
sp2
sp22py
120
H
ybridOrbitals
Non-bonding
B-1s22s22p1
H-1s1
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sphybrid
splinear
sp
sp
2p
2pz
180
Non-bonding
Be-1s22s2
H-1s1
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PenicillinG
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Themoleculebelowis
calledapyrrole.Thegeometryat
nitrogenistrigonalplanar.
Whatisthehybridizationatnitrogen?
A.
sp
B.
sp2
C.
sp3
D.
dsp3
Inwhat
orbitalaretheelectronsof
thelonepair
ofnitrogen?
A.sp
B.sp3
C.p
D.s
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