Why do the names of some ionic compounds include the charge of the metal ion while others do not?

The names of some ionic compounds include the charge of the metal ion while others do not because there are ionic compounds that are able to form more than one type of ion especially for metals and these compounds should be distinguished properly to avoid confusion. For instance, the metal cation of iron, we have Fe2 + and Fe3+. Ionic compounds with metal cations have a charge that is invariant from a compound to another does not include the charge of the cation. However, for ionic compounds of a metal with a charge that would vary in different compounds should include the charge of that particular metal cation.