Question

The molecule in which the central atom has one lone pair of electrons in its valence shell is

• A. \(CH_4\)
• B. \(BF_3\)
• C. \(BeCl_2\)
• D. \(NH_3\)

Answer 1

The Correct Option is D

To solve the problem, we need to identify the molecule in which the central atom possesses exactly one lone pair of electrons in its valence shell.

1. Analyzing the Molecules:
- CH₄ (Methane): Carbon forms 4 sigma bonds with hydrogen atoms. It has no lone pairs.
- BF₃ (Boron trifluoride): Boron forms 3 bonds with fluorine atoms and has an incomplete octet with no lone pairs.
- BeCl₂ (Beryllium chloride): Beryllium forms 2 bonds and also has an incomplete octet with no lone pairs.
- NH₃ (Ammonia): Nitrogen forms 3 bonds with hydrogen atoms and has 1 lone pair of electrons in its valence shell.

2. Conclusion:
Among the given molecules, only NH₃ has a lone pair on the central atom (nitrogen).

Final Answer:
The molecule is $ \text{NH}_3 $