I am writing out ionic compounds. The compound given is Fe(subscript)2O(subscript)3. I noticed on the periodic table iron had a charge of 3+/2+. Which should I then write down in the cation column of my ionic compound chart? Thank you.
You must figure it out.
All compounds are neutral.
Fe2O3 (you are correct that Fe can have oxidation states or valences of +2 as well as +3). So you look at oxygen. It is -2, -2*3 = -6; therefore, Fe must be +6 and since there are two of them each must be +6/2 = +3.
A compound like FeO has Fe of +2.
Then for the fun of it look at Fe3O4. Funny business going on there.