Table 2.1 Lewis structures of some common moleculesMolecule Lewis structures* H2H2 N 2, CO O 3, SO...
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Table 2.1 wis structures of some common m Molecule Molecule Lewis structures* Lewis structures* H 2 N 2 , CO 3 , SO 2 ,NO 2 - NH 3 , SO 3 2- C O 3- , SO 4 2- , ClO 4 - H H N N O O O S O O N O O N H H H 2- S O O O P O O O 3- O P O O O 2- O Cl O O O - O coordinate covale
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Transcript of Table 2.1 Lewis structures of some common moleculesMolecule Lewis structures* H2H2 N 2, CO O 3, SO...
Table 2.1 Lewis structures of some common moleculesMoleculeMoleculeLewis structures*Lewis structures*
H2
N2,CO
O3, SO2,NO2-
NH3, SO32-
C O
PO43-, SO4
2-, ClO4-
H H
N N
OOO SOON
OO
NH
HH
2-
SO
OO
PO
OO3-
OPO
OO2-
OClO
OO-
Ocoordinate covalent
N+O
OO- N2+O
OO- -
BF F
FB-F F
F+
two structures for BF3.
Formal Charge (F.C.)
Oxidation number of an element What is the oxidation n
umber of (a) nitrogen in the azide ion, and (b) manganese in the
permanganate ion,
,N3
.MnO4
(a) -3 1x O.N(N) = .
O.N.(N) =
.31
(b) O.N.(Mn) + 4 x O.N.(
-O) = 1
- - -O.N.(Mn) = 1 4x( 2 ) = +7.
Resonance
In fact these are call ed the the resonance
structures of the car bonate oxyanion.
O C O-
O- O- C OO- O- C O-
O
ResonanceOO O
OO
OO O = O
O+ O O
The BF3 molecule, for instance, is a re
sonance structuresResonance has two man effects: 1 . Resonance averages the bond
characteristicsover
2 . Resonance reduces t he energy of
the molecule any single contributing structure.
B FF
FB- FF
F+
Write resonance structures for the NO2F molecule and identify the dominant structures.
NF
O O+2
-1-10
NF
O O+1
0-10
NF
O O+1
-100
NF
O O+1
-1-1+1
Write resonance structures for the ion. :
2NO
N-O ON
O O-
Hypervalent compounds. : SF6, PCl5,
4ClO
23SO 3
4POI II III IV V VI VII VIII
H1s1
He1s2
Li1s22s1
Be1s22s2
B1s22s22p1
C1s22s22p2
N
1s22s22p3O
1s22s22p4F
1s22s22p5Ne
1s22s22p6
Na[Ne]3s1
Mg[Ne]3s2
Al
[Ne]3s23p1Si
[Ne]3s23p2P
[Ne]3s23p3S
[Ne]3s23p4
Cl
[Ne]3s23p5Ar
[Ne]3s23p6
K
[Ar]4s1
Ca
[Ar]4s2Br
[Ar]3s23p5
I
[Kr]3s23p2
Dative covalent bond.F
xxBx
xNxH
F Hx
xF H
xBF
FF N
H
HH or B
FF N
F
HH
H
Stoichiometry of c ovalent molecules
In this way the stoichio metry of covalentmolecul
es is determined by the number of valence electro
ns available for sharin g and forming two electro n pairs.
III IV V VI VIIOxyacid H3BO3 H2CO3 HNO3
Oxyanion [BO3]3- [CO3]
2- [NO3]-
Oxyacid H4SiO4 H3PO4 H2SO4 HClO4
Oxyanion [SiO4]4- [PO4]
3- [SO4]2- [ClO4]
-
Oxidation s2p1 s2p2 s2p3 s2p4 s2p5
Number of central atom +III +IV +V +VI +VII
