Download South Pasadena • AP Chemistry

Culver City H.S.  AP Chemistry
Name ___________________________________
Period ___ Date __/__/__
9  Bonding & Molecular Structure
ELECTRONEGATIVITY
1
H
2.1
3
Li
1.0
11
Na
1.0
19
K
0.9
37
Rb
0.9
55
Cs
0.8
87
Fr
0.8
1.
2.
4
Be
1.5
12
Mg
1.2
20
Ca
1.0
38
Sr
1.0
56
Ba
1.0
88
Ra
1.0
21
Sc
1.3
39
Y
1.2
57
La
1.1
89
Ac
1.1
22
Ti
1.4
40
Zr
1.3
72
Hf
1.3
23
V
1.5
41
Nb
1.5
73
Ta
1.4
24
Cr
1.6
42
Mo
1.6
74
W
1.5
25
Mn
1.6
43
Tc
1.7
75
Re
1.7
26
Fe
1.7
44
Ru
1.8
76
Os
1.9
27
Co
1.7
45
Rh
1.8
77
Ir
1.9
28
Ni
1.8
46
Pd
1.8
78
Pt
1.8
29
Cu
1.8
47
Ag
1.6
79
Au
1.9
30
Zn
1.6
48
Cd
1.6
80
Hg
1.7
5
B
2.0
13
Al
1.5
31
Ga
1.7
49
In
1.6
81
Tl
1.6
6
C
2.5
14
Si
1.8
32
Ge
1.9
50
Sn
1.8
82
Pb
1.7
7
N
3.0
15
P
2.1
33
As
2.1
51
Sb
1.9
83
Bi
1.8
8
O
3.5
16
S
2.5
34
Se
2.4
52
Te
2.1
84
Po
1.9
9
F
4.0
17
Cl
3.0
35
Br
2.8
53
I
2.5
85
At
2.1
In each pair of bonds, put a star () next to the more polar bond and use an arrow () to show the
direction of polarity in each bond.
a)
C—O
and
C—N
c)
B—O
and
B—S
b)
P—Br
and
P—Cl
d)
B—F
and
B—I
For each of the bonds listed below, indicate () which atom is the more negatively charged.
a) C—N
b) C—H
c) C—Br
d) S—O
It is somewhat artificial to classify bonds based on the differences in the electronegativities (X) of the two
atoms. However, we will use these ranges to do so:
Ionic
X  2.0
(symbolized as A+ and Z-)
Polar Covalent
1.7  X  .5
(symbolized as A+ and Z-)
Nonpolar Covalent X < .5
(no charges)
If the X is between 1.7 and 2.0 and if a metal is involved, then the bond is considered ionic.
If only nonmetals are involved, the bond is considered polar covalent.
3.
For each of the bonds listed below, classify each bond and indicate full or partial charges, if any.
a)
Na—Cl
e)
Mg—H
i)
Br—Br
b)
C—O
f)
Cs—F
j)
Na—Br
c)
Zn—O
g)
C—Cl
k)
H—F
d)
C—H
h)
Al—Cl
l)
C—S
Note about (j) and (k):
As you might expect, NaBr and HF are very different substances. NaBr exhibits the classic "lattice structure" of
ionic substances. HF is a corrosive gas and dissolves in water to form a weak acid. Both of these properties
indicate that HF is covalently bonded rather than forming ions.
Polar Bonds and Polar Molecules
Draw the Lewis structures for H2O (bent) and CO2 (linear).
In each case, the bonds are polar covalent.
Draw the arrow near each bond to show the bond polarity. Using vector analysis (physics or mathematics) draw
the resultant of the two arrow vectors. If there IS a resultant, the molecule is polar. If the vectors cancel, the
molecule is non-polar.
4.
For each of the following molecules, decide whether each molecule is polar or non-polar.
NH3
CS2
SO2
SN = ____
SN = ____
SN = ____
Bond Type ________________
Bond Type ________________
Bond Type ________________
Polar Molecule? ______________
Polar Molecule? ______________
Polar Molecule? ______________
PCl3
AlH3
GeF2
SN = ____
SN = ____
SN = ____
Bond Type ________________
Bond Type ________________
Bond Type ________________
Polar Molecule? ______________
Polar Molecule? ______________
Polar Molecule? ______________
5.
How would you classify the molecule, XeF4? Explain.