Question

Using the example of calcium chloride explain how the formulae of compounds are derived (given that the valency of calcium is 2 and that of chlorine is 1). ​

Answer 1

$CaCl_{2}$

Explanation:

• Firstly note down the symbols of the elements.

The elements in calcium chloride are calcium(Ca) and chlorine(Cl).

• Then note down the valencies as a superscript on the symbols of the elements.

The valency of calcium is 2 and chlorine is 1.

Therefore, we write the symbols as $Ca^{2}$ and​ $Cl^{1}$.

• If there is a common factor in the valencies, then divide it to a simple one.

In this case, the common factor among the numbers 1 and 2 is nil.

• The valencies are exchanged and written as subscripts to the elements.

Therefore, the formula of calcium chloride would be $CaCl_{2}$.