In an ionic compound, the ratio of positively and negatively charged ions is always a whole number. This ratio can be determined by the empirical formula of the compound. The empirical formula of an ionic compound gives the simplest whole number ratio of the elements present in the compound.

For example, consider the ionic compound sodium chloride (NaCl). The empirical formula of sodium chloride is NaCl, which means that there is one sodium ion for every one chloride ion in the compound. This is also the ratio of positively and negatively charged ions in sodium chloride.

Similarly, the empirical formula of calcium fluoride (CaF2) is CaF2, which means that there is one calcium ion for every two fluoride ions in the compound. This is also the ratio of positively and negatively charged ions in calcium fluoride.

The empirical formula of an ionic compound can be used to determine the compound's chemical formula. The chemical formula of an ionic compound gives the actual number of atoms of each element in the compound.

To determine the chemical formula of an ionic compound, we first need to know the empirical formula. Once we know the empirical formula, we can multiply the subscripts in the empirical formula by the appropriate integers to get the chemical formula.

For example, the empirical formula of sodium chloride is NaCl. To get the chemical formula, we need to multiply the subscripts in the empirical formula by 2. This gives us the chemical formula NaCl2, which is the molecular formula of sodium chloride.

Similarly, the empirical formula of calcium fluoride is CaF2. To get the chemical formula, we need to multiply the subscripts in the empirical formula by 2. This gives us the chemical formula CaF4, which is the molecular formula of calcium fluoride.