Naming cations

The IUPAC convention for naming cations is:

Element name(charge in roman numerals) + ion

We add the charge in roman numerals only if that element can form variable charges. For example, this is often true for transition metals like copper and iron.

For example iron(II) ion is the IUPAC name for Fe²⁺ and iron(III) ion is the IUPAC name for Fe³⁺