Question

Using the example of calcium chloride explain how the formula of compounds are derived (give that the valency of calcium is 2 and the chlorine is 1)

Answer 1

CaCl2
Ca chlorine
Valency 2 valency 1
By cross multiplication
Ca Cl =CaCl2
+2 - 1
In this way formula of compounds are derived.

Answer 2

Explanation:

The charge on calcium atom is 2 positive and charge on chlorine atom is 1 negative.

Therefore, to balance the charge we require two atoms of chlorine to react with one atom of calcium. Also, the compound is neutral thus net charge is zero.

The reaction will be as follows.

            $Ca^{2+} + 2Cl^{-} \rightarrow CaCl_{2}$