Inactive Tutor answered 11/24/23
Hello! The roman numberal tells you the charge of the first element (the metal), so in this case the charge of Tin is +4. Carbonate is a polyatomic (CO3) with a charge of -2. You can memorize the charges of polyatomcis, or refer to a polyatomic chart if your teacher allows. Therefore, the ions of Tin (IV) Carbonate are Sn4+ and CO32-. There is also a very helpful saying to help you learn and remember the polyatomics like carbonate (look up "Nick the Camel Ate a Clam for Supper in Phoenix" and study the explanation).