Final answer:
The metal that would not use a Roman numeral as part of its name in a compound is Ca, which stands for calcium.
Step-by-step explanation:
The metal that would not use a Roman numeral as part of its name in a compound is Ca, which stands for calcium.
Calcium is an alkaline earth metal and it typically forms ionic compounds with a charge of +2. Since calcium only has one common ionic charge, there is no need to use a Roman numeral to indicate its charge.
In contrast, metals like Cr (chromium), Mn (manganese), and Co (cobalt) can exhibit multiple ionic charges and require the use of Roman numerals to indicate their charge in a compound.