Chapter 4, Problem 4.26UKC

Interpretation Introduction

Interpretation:

The molecular model that doesn’t have a tetrahedral central atom in the given molecular models is to be identified.

Concept introduction:

Molecular shape can be predicted from the Lewis structure by using the valence-shell Electron-pair repulsion (VSEPR) model.

-Count the number of valence electron pairs (bond pairs and lone pairs).

-Assume that the valence electron pairs form a structure that allows them to be as far away from each other as possible.

-If there are only two bond pair electrons, the molecule is linear.

-If there are three bond pair electrons, the molecule is shaped like a trigonal planar.

-If there are four bond pair electrons, the molecule is shaped as a regular tetrahedral.

- Repulsion between lone pair-bond pair of electrons effect the geometry of molecules.

Bond angle is the angle between two bonds of a molecule and it is determined based on the geometry.

[Bond angles: $pyramidal<{\text{120}}^{\text{o}}$, $trigonalplanar={\text{120}}^{\text{o}}$, $tetrahidral={109.5}^{\circ }$]