Welcome to 3.091
Lecture 9
September 28, 2009
Drawing Lewis Structures
Potential energy (kJ/mol)
Total energy
Attractive interactions
Repulsive interactions
r = 180
0
Na+
Erep = bn
r
6 < n < 12
_
Cl
Internuclear distance, r (pm)
r0
r = 600
-589
r = 236
Born exponent
Na+
_
Cl
Na+
_
Cl
_ e2
EαH =
4π o r
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Public domain image from Wikipedia.
Public domain image from Wikipedia.
Period
Lewis Notation: Electron - Symbols (1916)
1A(1)
2A(2)
3A(13)
4A(14)
5A(15)
6A(16)
7A(17)
8A(18)
ns1
ns2
ns2np1
ns2np2
ns2np3
ns2np4
ns2np5
ns2np6
2
Li
Be
B
C
N
O
F
Ne
3
Na
Mg
Al
Si
P
S
Cl
Ar
Element symbol
Dots
Nucleus & inner es
Valence es
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Nonmetals have high χ
Electronegativity χ
Metal have
low χ
2
3
p
4
5
s
Copyright © 2003 John Wiley & Sons, Inc.
Reprinted with permission of John Wiley & Sons., Inc. Source: Spencer, J. N., G. M. Bodner, and
L. H. Rickard. Chemistry: Structure and Dynamics. 2nd edition. New York, NY: John Wiley & Sons, 2003.
Electronegativity, χ
4.0
3.0
2.0
1.0
0
0
10
20
30
40
50
60
Atomic number
70
80
Main groups 1-2 (s block)
Main groups 13-18 (s block)
Transition metals (d block)
Lanthanides (f block)
90
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1
2
3
4
5
6
7
1
18
H
He
13
14
15
16
17
B
C
N
O
F
2.04
2.55
3.04
3.44
3.98
Al
Si
P
S
Cl
12
1.61
1.90
2.19
2.58
3.16
Cu
Zn
Ga
Ge
As
Se
Br
1.91
1.90
1.65
1.81
2.01
2.18
2.55
2.96
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
2.2
2.28
2.20
1.93
1.69
1.78
1.96
2.05
2.1
2.66
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
1.7
1.9
2.2
2.2
2.2
2.4
1.9
1.8
1.8
1.9
2.0
2.2
Db
Sg
Bh
Hs
Mt
Ds
Rg
Uub Uut Uuq Uup
Ce
Pr
Nd
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
1.12
1.13
1.14
1.22
1.23
1.24
1.25
Actinides
Th
Pa
U
Np
Pu
Cf
Es
Fm
Md
7
1.3
1.5
1.7
1.3
1.3
2.20
2
Li
Be
0.98
1.57
Na
Mg
0.93
1.31
3
4
5
6
7
8
9
10
11
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
0.82
1.00
1.36
1.54
1.63
1.66
1.55
1.83
1.88
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
0.82
0.95
1.22
1.33
1.6
2.16
2.10
Cs
Ba
La
Hf
Ta
W
0.79
0.89
1.10
1.3
1.5
Fr
Ra
Ac
Rf
0.7
0.9
1.1
Lanthanides
6
0.7
3.98
1.17
1.20
Am
Cm
Bk
Ne
Ar
Kr
Xe
Rn
1.0
No
Lr
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Increasing
Increasing
Electronegativity, χ
s Block
p Block
d Block
f Block
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© source unknown. All rights reserved. This image is excluded from our Creative Commons
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© source unknown. All rights reserved.
This image is excluded from our Creative
Commons license. For more information,
see http://ocw.mit.edu/fairuse.
Figure removed due to copyright restrictions.
Chandler, David L. "MIT scientist shares Nobel
for identifying ozone damage." The Boston Globe,
October 12, 1995.
Nature, 249 June
Reprinted by permission from Macmillan Publishers Ltd: Nature © 1974. Source: Molina, Mario J., and Rowland, F. S. "Stratospheric sink for
chlorofluoromethanes: chlorine atomc-atalysed destruction of ozone." Nature 249 (June 28, 1974): 810-812.
28, 1974
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3.091SC Introduction to Solid State Chemistry
Fall 2009
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