Chem 111
1.
Molecules & Their Structures
Draw electron dot structures of the following ionic compounds formed from:
a) magnesium and oxygen
Mg
+2
O
-2
+
N
2.
3.
+2
C
+
S
-2
e) calcium and nitrogen
-3
3
c) calcium and carbon
2 Ca
Na
2
b) lithium and nitrogen
3 Li
d) sodium and sulfur
Ca
+2
2
N
-3
d) strontium and fluorine
-4
Sr
+2
2
F
-
What simple ion forms most commonly for the following elements?
a) Na +1
e) S
-2
b) I
-1
f) Mg
+2
c) K
+1
g) Al
+3
d) Ca +2
h) N
-3
Draw a Lewis structure for each of the following covalent molecules:
a) PH3
e) C2F6
F F
H P H
F C C F
H
F F
remember: a dash between 2 atoms = a pair of electrons in a bond
b) SiCl4
f) H2Se
Cl
Cl Si Cl
H Se H
Cl
c) CS2
g) BCl3
S C S
Cl B Cl
Cl
d) OCl2
Cl O
h) NCl3
Cl
Cl N Cl
Cl
4.
Draw Lewis structures of the following compounds that do not obey the octet
rule:
a) BrF3
d) IF5
FF
F
F I
Br F
F F
F
for clarity, lone pairs are only shown on the central atoms
b) XeF4
e) XeF2
F
F
F
F
Xe
F Xe F
c) SeF4
f) SCl6
F
Se F
F F
5.
F
F F
S
F F
F
Polyatomic ions consist of covalently-bonded atoms that, as a group, bear a
charge. Draw Lewis structures of the following polyatomic ions:
a) SO4-2
-
e) PO4-3
O
O S OO
-
b) SO3-2
-
O
O P OO-
f) ClO3-
O
O
S
O-
c) NO3-
g) NO2-
-
d) CO3-2
-
O
O
O
N+
O
C
O
-
-
O
O
N O
h) BrO2-
-
O
Cl OO
O Br O