Question

Identify the incorrect statement from the following:

• A. Nitrogen can form \(p\pi-p\pi\) multiple bonds with itself.
• B. \(P(CH_3)_3\) and \(As(CH_3)_3\) form \(d\pi-d\pi\) bond with transition metals.
• C. Nitrogen can form \(d\pi-p\pi\) bond with oxygen.
• D. Phosphorus, arsenic and antimony show catenation property.

Hint:

Second period elements such as nitrogen do not use \(d\)-orbitals for bonding.

Answer 1

The Correct Option is C

Step 1: Understanding the Topic:
The question covers the properties of "p-Block Elements," specifically Group 15 (The Pnictogens). A key concept here is the "anomalous behavior of Nitrogen," which arises because it belongs to the second period of the periodic table. Elements in the second period differ from their heavier congeners because of their exceptionally small size, high electronegativity, and, most importantly, the lack of vacant d-orbitals in their valence shell.
Step 2: Key Formulas and Approach:
The approach involves evaluating each statement based on the orbital availability of Nitrogen versus Phosphorus/Arsenic:
Nitrogen: Shell $n=2$, orbitals available: $2s, 2p$ (No d-orbitals).
Phosphorus/Arsenic: Shell $n=3$ or $n=4$, vacant d-orbitals available for bonding.

Step 3: Detailed Explanation:

Statement (A): Correct. Nitrogen is small and can achieve sideways overlap of p-orbitals to form the $N \equiv N$ triple bond.
Statement (B): Correct. Phosphines and Arsines use their vacant d-orbitals to accept electron density back from transition metals in a process known as "back-bonding" (forming $d\pi-d\pi$ bonds).
Statement (C): Correct. While Nitrogen shows limited catenation ($N_2, N_3^-$), Phosphorus and Arsenic show extensive catenation (chains and rings), as seen in $P_4$.
Statement (D): Incorrect. Nitrogen does not have any d-orbitals in its valence shell ($n=2$ can only have $l=0,1$). Therefore, it cannot participate in $d\pi-p\pi$ bonding. Heavy elements like Phosphorus can form such bonds with oxygen (as in $P_4O_{10}$).
Step 4: Final Answer:
The incorrect statement is (D).