A mnemonic is a technique used to help people remember certain rules about a specific topic or subject.

By using the mnemonic and the given information below, complete the question marks and the blanks:

Mnemonic:
"Could kNot Picture School"

- If Carbonate is CO3 with a charge of negative 2. And Phosphate is PO4 with charge of negative 3. Then Sulfate is SO? with a charge of *blank* and Nitrate is NO? with a charge of *blank*.