What is the electron geometry around the central phosphorus atom in PF3?

• A. Trigonal pyramidal
• B. Trigonal planar
• C. Tetrahedral
• D. Linear

Answer: (C)

Verified step by step guidance

1. Identify the central atom in PF3, which is phosphorus (P).
2. Determine the number of valence electrons on phosphorus. Phosphorus is in group 15, so it has 5 valence electrons.
3. Count the number of bonding pairs and lone pairs around phosphorus. PF3 has three fluorine atoms bonded to phosphorus, so there are 3 bonding pairs. Since phosphorus has 5 valence electrons and uses 3 for bonding, it has 2 electrons left, which form 1 lone pair.
4. Use the VSEPR (Valence Shell Electron Pair Repulsion) theory to predict the electron geometry. The total number of electron pairs (bonding + lone pairs) around phosphorus is 4 (3 bonding pairs + 1 lone pair). According to VSEPR, 4 electron pairs arrange themselves in a tetrahedral geometry to minimize repulsion.
5. Conclude that the electron geometry around the central phosphorus atom in PF3 is tetrahedral, even though the molecular shape (considering only atoms) is trigonal pyramidal.