Halogens 6.2
6.2 Oxidation Numbers
The
oxidation number of a group is the
number of e- required to make it
electronically neutral.
Elements & Compounds have an oxidation number of
ZERO.
Ions eg. X
n and [XYR]
n have an oxidation number of
n.
There are some rules to assigning oxidation numbers. These are shown below.
Oxidising raises the oxidation number of a group. Reducing lowers it. So oxidising agents are reduced and reducing agents are oxidised.
When balancing equations: calculate e- changes and then balance with O and H.
|
| Oxidation Number Rules
| | Group 1: | +1 | Group 2: | +2 |
| Al: | +3 | F: | -1 |
| H: | +1 | bar met. hydrides |
| Cl, Br, I | -1 | bar O or F |
| O: | -2 | bar peroxides or F | |