Question

Melting point of grp 1l5 increases from nitrogen to arsenic..but then decreases

Answer 1

Melting point increases from Nitrogen To As because -

-As we move down the group the number of shells increases and the Van der waals interactions increase .

-But elements after Nitrogen have d orbital in them which leads to screening effects.

Thus the force of attraction between the inner shells decreases which leads to a low melting point.