Question

Why +3 oxidation state is stable in heavier element of group15?

Answer 1

Higher oxidation states of heavier elements in group 15 are stabler because of Inert pair effect, i.e the inability of electrons of "s" subshell in taking place in bond formation

Answer 2

Group 15 elements mainly have consists having the nitrogen, phosphorus, arsenic, bismuth and antimony.

There is transition from non-metallic into the metallic with metalloid character.

Elements of nitrogen and phosphorus become arsenic, antimony and non-metals having the lastly aspects.

General valence mainly have the shell electronic configuration with the elements is ns2np3.

Orbital are completely filled with p orbital half filled.