Question

Calculate the valency of chlorine.

Answer 1

Valency is the combining capacity of the atom of an element or radical with the atoms of other elements or radicals.

Each atom of an element has a tendency to gain or lose electrons in order to get the stable outermost shell configuration(i.e. complete its octet).

Thus to calculate valency

• count the number of electrons in the outermost shell of the atom of an element if it is less than or equal to 4, then the valency remains equal to the number of electrons present in the valence shell.
• if the number of electrons in the outermost shell of the atom of an element is more than 4, then the valency of that element is calculated by subtracting the valence shell electrons from 8.

Valency of Chlorine:

The atomic number of Chlorine (Cl): 17

Electronic configuration of Chlorine:

There are seven electrons in the outermost shell that is more than 4 electrons so valency can be calculated by the following formula.

Valency=(8-valency electrons)

Valency of Chlorine= (8-7)=1

Valency of Chlorine =1.

Thus Chlorine requires one more electron in order to complete its octet, hence its valency is 1.