The charge on such an ion is specified in its formula, but not in its name. The charge is sometimes inferred from the position of the element in the periodic table, otherwise it must be memorized. A number of other metals form only one cation, or one common cation in aqueous solution.
Many transition metals form more than one cation.
This older nomenclature requires that you know the actual charges on the common ions. The cation is named using the name of the metal followed in parentheses by a Roman numeral indicating the magnitude of the positive charge. You must of course learn the modern naming system, but you must be familiar with the old system of nomenclature as well, since those names are still widely used. The ammonium ion is chemically similar to the alkali metal cations. Monatomic anions are named by dropping the ending of the element's name and adding the suffix - ide to the root.