Chem 212
Quiz 1g
p.1
NAME__________________________________
Lewis Str., VSEPR, Functional Groups (20 pts)
1. (9 pts) Each of the following molecules is a pollutant in our environment. Draw one Lewis
structure for the each, showing lone pairs and formal charges where necessary:
a. Ozone O3 (one of the oxygen atoms is the central atom)
There are two equivalent resonance structures; either one is an acceptable answer
:
-
O:
O
O
:
:
or
: :
O
:
: :
+
:
+
O
:
-
O
:
b. Dinitrogen monoxide N2O (one of the nitrogen atoms is the central atom)
There are three different resonance structures; any one of them would be an acceptable answer
O
+
or
N
+
N
-
: :
: :
:
:
:
+
N
2-
N
:
or
:
:
O
O
:
+
N
:
N
c. Sulfate anion, SO42Sulfur (and phosphorus, and others in the third row or below of the periodic table) can expand their octet.
-
:
: :
:
:
O
O
O
:
:
S
-
:
: O:
2. (3 pts) The structure below is related to a promising new class of anti-cancer drugs under
clinical investigation. What is the chemical formula for this molecule?
a
alkyne
OH
secondary alcohol
d
b
C10H8O2
O
alkene
ketone
c
3.
(4 pts) For the structure in question 2, use the VSEPR method to predict both the geometry
(linear, triangular planar, triangular planar/bent, tetrahedral, tetrahedral/triangular pyramidal,
tetrahedral/bent, octahedral) and bond angles around the atoms indicated by the arrows.
a. tetrahedral/bent, 104º (don’t forget the two lone pairs on oxygen!)
b.
tetrahedral, 109.5º (don’t forget the two H’s on carbon!)
c.
linear, 180º
d. triangular planar, 120º (don’t forget the H on the carbon!)
5. (4 pts) Circle and name three different functional groups in the structure in question 2.
see above for the answer