Determine the chemical formula of the following compounds. It is best to remember the symbols and charge values of these common ions, as shown in the Table.
(1) Sodium oxide, Na+ and O2-
(2) Magnesium oxide, Mg2+ and O2-
(3) Potassium bromide, K+ and Br-
(4) Iron(II) sulfate, Fe2+ and SO42-
(5) Iron(III) sulfate, Fe3+ and SO42-
(6) Ammonium sulfate, NH4+ and SO42-
Remember that the sum of the charges added together must always be zero.