What is the hybridization of the phosphorus atom in the molecule PCl5?

• A. sp3d
• B. sp
• C. sp2
• D. sp3

Answer: (A)

Verified step by step guidance

1. Identify the central atom in the molecule PCl5, which is phosphorus (P).
2. Determine the number of electron domains (regions of electron density) around the phosphorus atom. In PCl5, phosphorus is bonded to five chlorine atoms, so there are 5 bonding pairs and no lone pairs.
3. Recall that the hybridization corresponds to the number of electron domains: 2 domains = sp, 3 domains = sp2, 4 domains = sp3, 5 domains = sp3d, and 6 domains = sp3d2.
4. Since phosphorus has 5 bonding pairs, it has 5 electron domains, which corresponds to sp3d hybridization.
5. Conclude that the phosphorus atom in PCl5 is sp3d hybridized, which allows for a trigonal bipyramidal molecular geometry.