1)antimony tribromide _______SbBr3___
2)hexaboron silicide ____________B6S____________
3)chlorine dioxide ____________ClO2__________
4)iodic acid ________________HIO3______________
5)iodine pentafluoride ________IF5_______________
6)dinitrogen trioxide ____________N2O3______________
7)ammonia ________________NH3_________
8)hypophosphorous acid ______________H3PO2_____________
ANSWERS
9)
P4S5 ___tertaphosphorous pentasilicide____
10)
O2 ___oxygen__________
11)
HNO4 _____pernitric acid______
12)
Si2Br6 _____disilicon hexabromide____________
13)
SCl4 _____silicon tertachloride__________
14)
CH4 _____carbon tetrahydride___(methane)______
15)
H2SO3 ______sulfurous acid__________
16)
NF3 ________nitrogen trifluoride_____________
ANSWERS
9.3 Molecular Structure
Ball and
Stick
model
Stick
Model
Molecular Structures
Space Filling
Model
H2SO4
NH3
O
H
O
S
O
H
H
Water
O
H
H
O
H
N
CH4
H
H
H
Structural Formula
C
H
H
H2SO4
NH3
O
H
O
S
O
H
H
N
H
H
O
Water
CH4
H
H
O
H
Lewis Structure
H
C
H
H
1)
Predict Atom locations
C4H8O2
a) H is always terminal
b) Lowest Electronegativity
is central atom
H
C
2.55
O
3.44
General Lewis Structure Rules
1)
2)
Predict Atom locations
C4H8O2
a) H is always terminal
b) Lowest Electronegativity is
central atom
Find total number of
bonding e-
H– 1x8=8
C – 4 x 4 = 16
O – 6 x 2 = 12
36
General Lewis Structure Rules
1)
Predict Atom locations
C4H8O2
a) H is always terminal
b) Lowest Electronegativity
is central atom
2)
3)
Find total number of
bonding eFind number of pairs
36/2=18
General Lewis Structure Rules
1)
C4H8O2
Predict Atom locations
H
a) H is always terminal
b) Lowest Electronegativity
is central atom
2)
3)
4)
Find total number of
bonding eFind number of pairs
Place one bond
between central atom
and each outer atom
18
-13
5
H
H
C
H
C
O
O
C
H
C
H
H
H
General Lewis Structure Rules
1)
C4H8O2
Predict Atom locations
H
a) H is always terminal
b) Lowest Electronegativity is
central atom
2)
3)
4)
5)
Find total number of
bonding eFind number of pairs
Place one bond between
central atom and each
outer atom
Place remaining e- pairs
around outer atoms
18
-13
5
H
H
C
H
C
O
O
C
H
C
H
H
H
General Lewis Structure Rules
1)
C4H8O2
Predict Atom locations
H
a) H is always terminal
b) Lowest Electronegativity is
central atom
2)
3)
4)
5)
6)
Find total number of bonding
eFind number of pairs
Place one bond between
central atom and each outer
atom
Place remaining e- pairs
around outer atoms
Form double (triple) bonds to
give central atom an octet
H
H
C
H
C
O
O
C
H
C
H
H
H
General Lewis Structure Rules
Cations
NH4+ 8
Anions
Sulfate 26
H – 1x4=4
N – 5x1=5
9
S – 6x1 = 6
O – 6x4 = 24
30
(+) =
(2-)
-1
8
Polyatomic Ions
=2
32
Cations
NH4+ 8
Anions
Sulfate 26
+
H
H
N
H
H
Polyatomic Ions
2-
O
O
S
O
O

C 2 H6

N2

CO2

O3
H
O
H
H
C
C
H
H
C
H
N
N
O
Get to Work
Draw Structural Formulas

O3
O
O
O
O
Resonance
O
O
A molecule has
resonance when
you can draw
multiple Lewis
Structures
NO3-
-
O
N
O
O
Resonance Structures
A molecule has
resonance when
you can draw
multiple Lewis
Structures
NO3-
-
O
N
O
O
Resonance Structures

O3
O
O

O
SO2
S
O
Second Chance
O
I.
Odd number of e-
II.
Fewer than 8 e-
NO2
BH3
O
N
O
H
B
H
H
III.
Expanded Octet
SF6
F
F
Exceptions
F
S
F
F
F
Fewer than 8 eCoordinate Covalent Bond
1 atom donates both e- to share
H
H
H
B
N
H
H
Exceptions
H