You don't without having additional information. If you were given this compound Fe2O3, you would first recognize that oxygen most likely has a 2 minus charge associated with it, since there are three oxygens, that would be a total of 6 minus. The irons must neutralize that 6 minus by having a total of 6 plus. Since there are two irons each one must have a 3 plus charge associated with it.
fe+3=..............* .9 =fe+2
Ag+
2+, since carbonate (CO3) has a 2- charge.
fe+3
2 Fe + 3 CuO -> Fe2O3 + 3 Cu
Fe 2+ is Ferrous Fe 3+ is Ferric
fe+3=..............* .9 =fe+2
A. Fe^2+ ==> Fe^3+ + e- is an oxidation reactionB. Fe^3+ +e- ==> Fe^2+ is a reduction reactionC. Fe(s) ==> Fe(l) is neither an oxidation nor a reduction reaction. It is a phase change.D. Fe + 2e- ==> Fe^2+ is not a possible reaction.
The net charge is the charge that there is more of in an object. For example, if an object has 5 electrons (negative charges) and 4 protons (positive charges), then the net charge is negative because there are more electrons in the object. If the object gains 2 protons through the transfer of electric charge then the net charge becomes positive. However, if the object loses 1 proton to have an equal amount of both protons and electrons, then the net charge becomes nuetral.
Ag+
Fe 2+ is Ferrous Fe 3+ is Ferric
This is the ion Fe(3+).
Fe(NH4)3 but b sure to make the numbers subscript
Iron Oxide is Fe[2]O[3] and Nitric acid is HNO[3]
Sulfides have a minus 2 charge, so the iron in iron sulfide has a charge of +2.
3FeO4 + 8Al --> 3Fe + 4Al2O3
This indication is in parenthesis, with Latin numerals: Fe(II), Fe(III).