Question

In case of phosphorus, PCl$_{3}$ and PCl$_{5}$ are possible while nitrogen only forms NCl$_{3}$ and not NCl$_{5}$. This is due to:

• A. Nitrogen is a gas while phosphorus is a solid at room temperature.
• B. Nitrogen does not have vacant d-orbitals in its atom while phosphorus has vacant d-orbitals.
• C. The electronegativity of nitrogen is higher than that of phosphorus.
• D. The atom of nitrogen is smaller in size than phosphorus.

Hint:

The ability to form multiple bonds, like in PCl$_{5}$, depends on the availability of vacant d-orbitals in the element’s valence shell. Phosphorus can use its 3d orbitals, but nitrogen cannot, limiting its bonding capabilities.

Answer 1

The Correct Option is B

Nitrogen only forms NCl$_{3}$ and not NCl$_{5}$ due to the absence of vacant d-orbitals in its valence shell. Phosphorus, on the other hand, has vacant d-orbitals in its 3d subshell, which allows it to expand its valence shell and form PCl$_{5}$, a stable compound. Nitrogen lacks these orbitals, so it cannot form a five-bond structure with chlorine, making NCl$_{5}$ impossible.