2. How do you determine the charges on the ions in an ionic compound?

In ionic compounds, the charges on the ions are determined by the number of electrons donated to or accepted by each ion.

Ionic compounds are formed when a bond is formed between two atoms as a result of electron donation from one atom and electron acceptance by the other.

Thus, the charge on each ion would depend on the number of electrons donated or accepted. An atom that donates electrons will carry a positive charge with the number of electrons donated while an atom that accepts electrons will carry a negative charge with the corresponding number of accepted electrons.

For example, NaCl is an ionic compound formed by the combination of Na and Cl atoms. Na donated its single valence electron to Cl. Hence, in ionic form, the Na atom who donated an electron would be while the Cl atom that accepted an electron would be

More on ionic compounds can be found here: link