Which of the following best describes the electron geometry of PF3?

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

Answer: (D)

Verified step by step guidance

1. Determine the total number of valence electrons around the central atom, phosphorus (P). Phosphorus has 5 valence electrons, and each fluorine (F) atom contributes 1 electron, so for PF3, calculate the total valence electrons accordingly.
2. Draw the Lewis structure of PF3 by placing phosphorus in the center and connecting it to three fluorine atoms with single bonds. Then, distribute the remaining electrons to satisfy the octet rule for each atom.
3. Count the regions of electron density (bonding and lone pairs) around the central phosphorus atom. Each bond counts as one region, and any lone pairs on phosphorus count as additional regions.
4. Use the VSEPR (Valence Shell Electron Pair Repulsion) theory to determine the electron geometry based on the number of electron density regions. For example, 4 regions correspond to a tetrahedral electron geometry.
5. Identify the molecular shape by considering the positions of atoms only (ignoring lone pairs), but remember that electron geometry includes both bonding pairs and lone pairs, so the electron geometry of PF3 is tetrahedral.