Answers to Amar and Katy

Hi all,
Amar, you can memorize the electrolysis half reactions in acidic and KNO3 media (because these are the only two cases that may come up)
Katy, the compounds I gave you are not molecular: for example MgSO4 is an ionic compound, Mg2+ is a metalic ion, and sulfate ion is a nonmetal. so the oxidation number of mg is equal to its charge. Did I answer your question? if not, tell me.