Question

Explain why +5 oxidation state is most stable for group 15 elements?

Answer 1

Dear student,

In group 15, the elements N, P, As, Sb, Bi
N does not form a +5 oxidation state compound because N can not form 5 bonds because of the unavailability of a 2d shell.
P can form Penta halide (+5 oxidation state compound) and is most stable because of the presence of 3d shells.
As we move down in the group due to inert pair effect of s-orbital +3 oxidation state becomes more stable than +5 oxidation state;

Inert pair effect is shown by elements present down in the group and their ns² e does not take part in bond formation hence known as inert pair effect and +3 oxidation state becomes more stable than +5 state.

So, we can say that top to bottom in the group- 15 elements stability of +5 oxidation state compounds decreases whereas the stability of +3 oxidation states compounds increases.

Regards