09-20-2018, 06:32 AM
The metallic aluminum atoms donate three electrons to be become Al+3 ions. Sulfite, a polyatomic ion, is SO3 -2. Ionic compounds form when the ratio of positively charge ions (cations) to negatively charged ions (anions) results in no electrical charge. The two aluminum ions contribute a +6 electric charge. Three sulfite ions contribute a -6 electric charge. Therefore, the ratio of cations to anions results in no electric charge.