Naming compounds that contain multicharged ions?

I am taking Chemistry 1070. We are studying polyatomic ions. On my study guide I thought the name for the compound, SnO was stannous oxide, but on the answer sheet my professor has tin II oxide. How do I know when to use stannous and when to use tin II, the same goes for how do I know when to use plumbic and when to use lead IV?

Naming compounds that contain multicharged ions?
Ok, well Tin (II) is the same as Stannous, just as Tin (IV) is the same as Stannic, you can use the names back and forth and its the same thing (stannous and stannic are just older names for Tin (II) and Tin (IV)). The same goes for lead, theres Pb (II) and Pb (IV) (Plumbous and Plumbic respectively).
Reply:It's easy, go with whatever the professor says. Stannous oxide here would be the common name, and tin 2 oxide would be the chemical name, I'm assuming the names you've given are correct. Its like water and dihydrogen monoxide.