Which molecule has a lone pair on the central atom and a pyramidal shape?
Answer and explanation
Correct answer: A.
- Step 1: According to VSEPR theory, a trigonal pyramidal molecular geometry arises from an steric arrangement (three bonding pairs and one lone pair).
- Step 2: In ammonia (), the central nitrogen atom has valence electrons: form single bonds with hydrogen atoms and the remaining form one non-bonding lone pair.
- Step 3: The lone pair exerts greater repulsive force than bonding pairs, distorting the tetrahedral domain geometry into a trigonal pyramidal shape with bond angles of approximately .
Answer
.
Why not the others: is tetrahedral with zero lone pairs; is trigonal planar with an incomplete octet and zero lone pairs; is linear with zero lone pairs on carbon.
Practise more Chemical bonding.
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