what does an -ite or -ate ending in a polyatomic ion mean? i'm thinking it mean Oxygen is in the formula, or is it Sulfur is in the formula? i'm not sure

oxygen is in both ites and ates. The ate has more oxygen than ite.
NaClO2 sodium chlorite
NaClO3 sodium chlorate
NaClO4 sodium PERchlorate (more O than ate).
NaClO sodium HYPOchlorite (less O than ite).

is this the correct name for N3-

Nitride ion

I assume that is a -3 charge as in
N-3. Yes, it is the nitride ion. Magnesium nitride is

Mg3N2

thanks

Yes, you are correct! The ending "-ide" is usually used to indicate a negative ion. In the case of the nitride ion, it means that the ion has a charge of -3. So, N3- is called the nitride ion.

To name a compound that contains the nitride ion, you would typically use the name of the metal or positive ion followed by the name of the negative ion with the "-ide" ending. For example, in the compound Mg3N2, the metal ion is magnesium (Mg) and the negative ion is nitride (N), so the compound is named magnesium nitride.

I hope this explanation helps! Let me know if you have any other questions.