How will you find the valency of chlorine, sulphur and magnesium?
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We know that an element’s valency refers to its proclivity for accepting or losing electrons in order to complete its octet and achieve a stable electronic state.
It is the smallest number of electrons that must be added or removed to entirely occupy an element’s outermost shell.
Mathematically, if an atom’s outermost shell contains 4 or fewer electrons, the element’s valency is equal to the number of electrons present in the outermost shell; if it contains more than 4, the valency is determined by subtracting the total number of electrons present in the outermost shell from 8.
Calculation of valency:
Valency of chlorine:
The electronic configuration of chlorine = 2, 8, 7
Chlorine has 7 (more than 4) electrons in its outermost shell.
Therefore, the valency of chlorine = 8 – the number of electrons in the outermost shell
= 8−7
= 1
Valency of Sulphur:
The electronic configuration of Sulphur = 2, 8,6
Sulphur has 6 (more than 4) electrons in its outermost shell.
Therefore, the valency of chlorine = 8 – the number of electrons in the outermost shell
= 8−6
= 2
Valency of magnesium:
The electronic configuration of Magnesium = 2, 8, 2
Magnesium has 2 (less than 4) electrons in its outermost shell.
Therefore, the valency of magnesium= Number of electrons in its outermost shell
= 2