Question

Why does stability of hydrides decrease down the group 15?

Answer 1

The stability of hydrides decreases from ammonia to bismuthine. This is because the central atom E increases in size down the group. With the increase in the size of the central atom, the E – H bond becomes weaker. where E is nitrogen ,phosphorus, arsenic,antimony , bismuth.

With the increase in size, the overlapping between the orbitals of E and hydrogen will not be effective. This accounts for the decrease in the stability of hydrides as we move down the group