Chemistry Reference
In-Depth Information
Solution
In this compound, the oxidation number of each chlorine atom is (rule 8).
To make the total of all the oxidation numbers for equal zero, the phos-
phorus must have an oxidation number of To do this calculation systemat-
ically, let
x
equal the oxidation number of phosphorus in
1
PCl
5
5.
PCl
5
.
Then
x
5(
1)
0
Oxidation
number of
phosphorus
Number of
chlorine
atoms
Oxidation
number of
each chlorine atom
Charge
on the
molecule
x
5
Practice Problem 16.1
Determine the oxidation number of carbon
in CO.
EXAMPLE 16.2
What is the oxidation number of Mg?
Solution
Zero. (This is elemental magnesium.)
EXAMPLE 16.3
NO
2
?
What is the oxidation number of nitrogen in the nitrite ion,
Solution
The oxidation number of oxygen in most of its compounds is (rule 7). The
oxidation numbers of the two oxygen atoms plus that of the nitrogen atom must
total
2
1
,
the charge on the ion:
x
2(
2)
1
Oxidation
number of
nitrogen
Number of
oxygen
atoms
Oxidation
number of
each oxygen atom
Charge
on the
nitrite ion
x
3
Practice Problem 16.3
What is the oxidation number of sulfur in the
sulfite ion, SO
2
?
3
