To write the formula for an ionic compound write the formulas for the cation and the anion then use subscripts to what charges?

To write the formula for an ionic compound, you first write the symbol for the cation (positively charged ion) followed by the symbol for the anion (negatively charged ion). Then, you use subscripts to indicate the ratio of ions needed to balance the charges to make it electrically neutral. The subscripts are the smallest whole numbers that will ensure the compound has a net charge of zero.