Determine the molecular geometry and sketch each molecule or ion, using the bond conventions shown in 'Representing Molecular Geometries on Paper' in Section 10.4. c. PF₅

Verified step by step guidance

1. Determine the total number of valence electrons in PF_5. Phosphorus (P) has 5 valence electrons, and each fluorine (F) has 7 valence electrons. Calculate the total valence electrons for the molecule.
2. Identify the central atom. In PF_5, phosphorus (P) is the central atom because it is less electronegative than fluorine (F) and can form more bonds.
3. Use the VSEPR (Valence Shell Electron Pair Repulsion) theory to determine the molecular geometry. PF_5 has 5 bonding pairs and no lone pairs on the central atom.
4. According to VSEPR theory, a molecule with 5 bonding pairs and no lone pairs on the central atom adopts a trigonal bipyramidal geometry.
5. Sketch the molecule using the bond conventions: draw three bonds in the plane of the paper (120° apart), one bond coming out of the plane (wedge), and one bond going into the plane (dash).

Key Concepts

VSEPR Theory

Valence Shell Electron Pair Repulsion (VSEPR) Theory is a model used to predict the geometry of individual molecules based on the repulsion between electron pairs in the valence shell of the central atom. According to VSEPR, electron pairs will arrange themselves as far apart as possible to minimize repulsion, leading to specific molecular shapes.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. It is determined by the number of bonding pairs and lone pairs of electrons around the central atom, which influences the overall shape, such as linear, trigonal planar, tetrahedral, or octahedral, among others.

Phosphorus Pentafluoride (PF5)

Phosphorus pentafluoride (PF5) is a chemical compound consisting of one phosphorus atom bonded to five fluorine atoms. The molecular geometry of PF5 is trigonal bipyramidal, which arises from the arrangement of five bonding pairs of electrons around the phosphorus atom, with no lone pairs affecting the geometry.