Question

What are the differences between oxidation numbers and ionic charge? Do I have to write e.g Al3+ or Al+3?

Answer 1

the oxidation number of an atom is the charge that atom would have if the compound was composed of ions. 1. ... The oxidation number of simple ions is equal to the charge on the ion. The oxidation number of sodium in the Na+ ion is +1, for example, and the oxidation number of chlorine in the Cl- ion is -1.