Final answer:
To name an ionic compound with a transition metal, include the metal's oxidation state using Roman numerals in parentheses after the metal's name, e.g., iron(III) chloride for FeCl₃.
Step-by-step explanation:
When writing the name of an ionic compound that includes a transition metal, it is important to include the oxidation state of the metal. Transition metals can have more than one possible ion formation, so the oxidation state indicates which ion is present in the compound. This is shown using Roman numerals in parentheses immediately after the name of the metal.
For example, the iron-containing compound FeCl₃ requires specifying the oxidation state of iron because iron can form ions with different charges. In this case, iron has a charge of 3+, so the compound is named iron(III) chloride. Similarly, a compound with the formula FeCl₂ would be named iron(II) chloride since the iron ion has a charge of 2+.