Q. 1. How will you find the valency of chlorine, sulphur, and magnesium?
Valency is basically the minimum number of electrons we have to add or remove so that every shell in the atom is completely filled.
Mathematically,
When the outermost shell of an atom contains 4 or less than 4 electrons, its valency is equal to the number of valence electrons in the outermost shell and when the outermost shell contains more than 4 electrons, the valency of the atom is equal to the number of valence electrons in the atom.
Chlorine :
Atomic No. of Cl = 17
Its electronic configuration = 2, 8, and 7
Valency of Cl = 8 - 7 = 1
Sulphur :
Atomic no. of S = 16
Its electronic configuration = 2, 8, 6
Valency of S = 8 - 6 = 2
Magnesium:
The atomic no. of Mg = 12
Its electronic configuration = 2, 8, 2
Valency of Mg = 2