What is the formula for the ions in the compounds BaSO4 and Li2CO3

BaSO4 has barium ions (Ba²⁺, Sulfate ions SO₄^{2-,

and Lithium carbonate has lithium ions Li¹⁺, and carbonate ions CO₃^{2-

Ba ions (might be written as Ba^2+) and sulfate (might be written as SO4^2-).

Li^1- and CO3^2-.

I think the idea behind this question is for the student to realize that the Ba is there as one entity of the ionic bond but the sulfate ion is made up of covalent bonds and it is the other entity. Same kind of thing for the lithium carbonate.}}