Final answer:
When a cation has more than one ionic charge, a Roman numeral is used in its name to indicate the specific charge, such as iron(II) for Fe²⁺.
Step-by-step explanation:
When a cation has more than one ionic charge, a Roman numeral is used in the name to indicate its charge. For example, iron(II) and iron(III) are names for Fe²⁺ and Fe³⁺ ions, respectively. Similarly, copper(I) and copper(II) are used for Cu⁺ and Cu²⁺. In naming ionic compounds, such as FeCl₂ and FeCl₃, you must determine the charge of the cation first and then use it in the compound's name, resulting in iron(II) chloride and iron(III) chloride respectively.