3. What happens to the change on individual ions when they form ions?

11. Write the names of the two ions in each of the following compounds.
(C) Na2O
(E) Na3PO4
(G) NH4OH
(H) Ca (NO3)2

8. Use the tables of metals, non-metals, and polyatomic ions and the Periodic table to name the following ionic compounds.
(E) Mg3N2
(F) Fe2(CO3)3
(G) Cr2O3
(H) Al2(SO4)3
(I) Cu2SO4
(J) Pb(NO3)4

I do not understand these questions, even though I have read over the material lots of times. I struggle in chemistry. :(
Thanks for your time and help