Find oxidation number of a metal in a compound Calculate the oxidation number of $\ce{Fe}$ in $\ce{Fe2O3}$.




Alright. So we have a metal and an non metal. This means that iron will lose electrons and give them to oxygen. So it will be a positive oxidation number for iron I guess.

The question is, how much? A wild guess is $2+$ because, well, each iron would is bound to two oxygens so I imagine each oxygen will take one electron each?
Oxidation number of Fe is +3. This is because oxygen has a charge of -2. There are 3 oxygen atoms. So net charge becomes -6. Thus to balance it, each of the 2 Fe atoms must have a charge of +3 (-6 + 6 = 0).