Valency of Chlorine, Sulphur and Magnesium

How Do You Find the Valency of Chlorine, Sulphur and Magnesium?

Valency is the definite combining capability of each element’s atoms, where electrons are lost, acquired, or shared to form the octet of electrons present in the outermost shell. To calculate valency, we can calculate the number of electrons required to fill the shell in which it is stored, or the number of electrons lost if surplus electrons are present, once the filling is complete.

• If the number of electrons in the outermost shell of the atom of an element is less than or equal to 4, then the valency of the element is equal to the number of electrons in the outermost shell.
• On the other hand, if the number of electrons in the outermost shell of the atom of an element is greater than 4, then the valency of that element is determined by subtracting the number of electrons in the outermost shell from 8.

Valency of Chlorine

The atomic number of Chlorine is 17

• The electronic configuration of chlorine is [Ne]3s² 3p⁵or can also be written as 2,8,7.
• This shows chlorine has 7 valence electrons in its outermost shell.
• If there are more than four valence electrons, the valency can be calculated as Valency = Valence electron -8.
• As a result, chlorine has a valency of 7-8, which is -1.

Valency of Sulphur

The atomic number of Sulphur is 16

• The electronic configuration of sulfur is (S) [Ne] 3s¹ .
• So, in order for Sulphur to acquire stability, it must gain two electrons.
• The valency of Sulphur = 8 – 6 = 2
• Therefore, the valency of Sulphur is 2.

Valency of Magnesium

The atomic number of magnesium is 12

• The electronic configuration of magnesium is [Ne]3s² or can also be written as 2,8,2.
• This shows magnesium has 2 valence electrons in its outermost shell.
• Valency is defined as the number of valence electrons less than four.
• Magnesium has a valency of 2 because it has two valence electrons.