In this compound: Li is +1, Cl is +3 and O is -2.
This is called lithium chlorite. The ions that are present is Li+ and ClO-2
The oxidation number of an element is the charge on the atom if and only if the compound is entirely ionic.
Oxygen has a charge of -2.
So in ClO-2, the oxygens contribute 2 x -2 = 4.
But you know that the charge on the ion is -1, then Cl must be +3. Solution:
Li+ Cl + 2O = 0
+1 + Cl + 2(-2) = 0
Cl = +3
So the net charge would be:+ 3 - 4 = -1.
In Li+ the oxidation state of it must be +1 and Chlorine is +3.
