Ans.
1. The valency of an element is determined by the number of electrons present in the outermost shell (valence electrons) of its atoms.
2. From the electronic configuration of an element, one can determine the number of valence electrons.
3. The valency is equal to the number of valence electrons for elements having 1 to 4 valence electrons.
4. For elements having 5 to 8 valence electrons,
The valency = 8 - Number of valence electrons.
