Write the formula for the following ionic compounds that include metals with variable charge: a) Tin (IV) oxide b) Copper (I) sulfide c) Gold (III) bromide d) Nickle (III) sulfide Write out the formula for the polyatomic ion with its charge and then name each of the following ionic compounds: a) Al(NO3)3 b) K2CO3 c) Ni(CN)2 d) BaSO4 e) Na2C2H3O2 f) (NH4)2S