How dould you account for the following :
The stability of +5 oxidation state decreases down the group 15 of the periodic table.

Explanation

(a) This is due to inert pair effect.
(b) The elements can show +4 oxidation state only when the electron from `ns^2` gets excited to np orbitals.
(c ) As the vlue of n increases the `ns^2` electron parir becomes more reductant in getting excited and taking part in bond formation.
(d) So the stability of +4 oxidation state decreases going down the group.