How to find the Oxidation Number for Fe in Fe2O3

To find the correct oxidation number for Fe2O3 (Iron (III) oxide), and each element in the compound, we use a few rules and some simple math. First, since the Fe2O3 doesn’t have an overall charge (like NO3- or H3O+) we could say that the total of the oxidation numbers for Fe2O3 will be zero since it is a neutral compound. We write the oxidation number (O.N.) for elements that we know and use these to figure out oxidation number for Fe. ---------- GENERAL RULES In a netural compound all O.N. must add up to zero. Group 1 = +1 Group 2 = +2 Hydrogen with Non-Metals = +1 Hydrogen with Metals (or Boron) = -1 Fluorine = -1 Oxygen = -2 (except in H2O2 or with Fluorine) Group 17(7A) = -1 except with Oxygen and other halogens lower in the group ---------- We know that Oxygen usually is -2 with a few exceptions. When Oxygen is in a peroxide, like H2O2 (Hydrogen peroxide), it has a charge of -1. When it is bonded to Fluorine (F) it has an oxidation number of +2. Here it is bonded to element symbol so the oxidation number on Oxygen is -2. Using this information we can figure out the oxidation number for the element Fe in Fe2O3.