Identify the incorrect statements about group 15 elements :
(A) Dinitrogen is a diatomic gas which acts like an inert gas at room temperature.
(B) The common oxidation states of these elements are -3,+3 and +5.
(C) Nitrogen has unique ability to form p π-p π multiple bonds.
(D) The stability of +5 oxidation states increases down the group.
(E) Nitrogen shows a maximum covalency of 6.
Choose the correct answer from the options given below :

Solution

Chemistry ma’am · 2 steps

Two facts settle this: nitrogen has no d orbitals, and the inert pair effect grows down the group.

1. Check each statement. Judge all five statements one at a time. Then pick the option that lists exactly the false ones.

   Statement	True or false	Reason
   (A) N₂ is inert at room temperature	True	The N≡N triple bond is very strong (about 941 kJ mol⁻¹), so N₂ hardly reacts at room temperature.
   (B) Common states are -3, +3, +5	True	With configuration ns²np³, the atom can gain 3 electrons, use its 3 p electrons in bonding, or use all 5.
   (C) N forms pπ–pπ multiple bonds	True	N is small and highly electronegative, so its p orbitals overlap well side by side, as in N≡N.
   (D) Stability of +5 increases down the group	False	The inert pair effect makes +3 more stable going down, so +5 becomes less stable. NaBiO₃, with Bi in +5, is a strong oxidant.
   (E) Maximum covalency of N is 6	False	N has no d orbitals, only one 2s and three 2p. Its maximum covalency is 4, as in NH₄⁺.

2. So. Only (D) and (E) are incorrect, which is option (b).

The idea to keep. Period 2 elements have no d orbitals, so their covalency stops at 4. Down groups 13 to 15, the inert pair effect makes the lower oxidation state more stable.

Answer from the NTA final answer key. Solution by PrepWiser.