Discuss the trends in chemical reactivity of group 15 elements.

Explanation

General trends in chemical properties of group − 15
(i) Reactivity towards hydrogen:
The elements of group 15 react with hydrogen to form hydrides of type `EH_(3)`, where E = N, P, As, Sb, or Bi. The stability of hydrides decreases on moving down from `NH_(3)` to `BiH_(3)`.
(ii) Reactivity towards oxygen:
The elements of group 15 form two types of oxides: `E_(2)O_(3)` and `E_(2)O_(5)`, where E = N, P, As, Sb, or Bi. The oxide with the element in the higher oxidation state is more acidic than the other. However, the acidic character decreases on moving down a group.
(iii) Reactivity towards halogens:
The group 15 elements react with halogens to form two series of salts: `EX_(3)` and `EX_(5)`. However, nitrogen does not form `NX_(5)` as it lacks the d-orbital. All trihalides (except `NX_(3)`) are stable.
(iv) Reactivity towards metals:
The group 15 elements react with metals to form binary compounds in which metals exhibit `−3` oxidation states.