Split the compound, atom by atom, leaving them in the order they are written. Example, H2SO4 -> 2H + S + 4O.
Examine each atom and assign to it its proper oxidation state. This information is found on any standard periodic table. In our example, hydrogen has a +1 oxidation state, sulfur a +6 state and oxygen a -2 state.
Group the most potent charges together. Example, sulfur and oxygen have the most powerful charges and will attract each other more strongly than hydrogen and oxygen.
Place the atoms in their chemical compound form. From above, 2H becomes H2 and 4O becomes 2 O2.
Combine the charges of the grouped atoms. Sulfur at +6 combined with 4 O at -2 becomes SO4 -2. The 4 oxygen provide a -8 charge while the sulfur provides a +6 charge.
Examine all species and determine if there are any groups with non-neutral charges. In our example, SO4^-2 is an ionic compound with more than one atom, making it polyatomic. The H2 is a single atom species with a +2 charge. The hydrogen is known as a monoatomic, not polyatomic, ion.