How can you find an oxidation number?
1 Answer
Jun 18, 2016
You can work them out based on the following rules for oxidation states.
-
All uncombined elements have an oxidation number of zero:
eg. Na,#O_2# ,#F_2# -
Compounds are always neutral overall: so all oxidation numbers in it add to zero:
eg. NaCl is neutral.
Na is Na+ and Cl is Cl- -
Some elements always have the same oxidation state:
- Group 1 are +1
- Group 2 are +2
- Aluminium is +3
- Fluorine is -1
-
Others can be tricksy based on the compounds they are in:
- Hydrogen always +1 except in metal hydrides (like NaH) where it is -1
- Oxygen always -2, except in peroxides, superoxides, and
#OF_2#