Question

What is the net charge of the ionic compound calcium fluoride?

Answer 1

$Ca{F}_2$ is conceived to be formed of 2 ions, $C{a}^{2+}$, and $F^{-}$. Clearly, there must be 2 negative ions to balance the 2 positive charges of the metal ion.

The mineral itself, fluorite, is prized for its optical properties, and exhibits very low solubility in water on the basis of its structure.