1. List the polyatomic cations.
2. How many polyatomic ions of chromium are there? Write out the formulas and names each ion.
3. How many polyatomic ions of chlorine are there? Write out the formulas and name each ion
4. Write the formulas for the following ions:
   1. ammonium
   2. carbonate
   3. sulfate
   4. phosphate
5. Name the following ions:
   1. PO₃^3-
   2. SiO₃^2-
   3. OH^-
   4. MnO₄^-