Choose the shape (1 to 6) that matches each of the following descriptions (a to c): 1. linear2. bent (109°)3. trigonal planar4. bent (120°)5. trigonal pyramidal6. tetrahedralb. a molecule with a central atom that has four electron groups and three bonded atoms

Verified step by step guidance

1. Identify the number of electron groups around the central atom. In this case, there are four electron groups.
2. Determine the number of bonded atoms. Here, there are three bonded atoms.
3. Recognize that the presence of four electron groups around the central atom typically suggests a tetrahedral electron geometry.
4. Consider the effect of lone pairs. With three bonded atoms and one lone pair, the molecular shape is affected.
5. Conclude that the molecular shape with three bonded atoms and one lone pair is 'trigonal pyramidal'.

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 surrounding a central atom. According to this theory, electron groups (bonding and lone pairs) will arrange themselves to minimize repulsion, leading to specific molecular shapes.

Electron Groups

Electron groups refer to regions of electron density around a central atom, which can include bonded atoms and lone pairs. The number of electron groups determines the molecular geometry; for example, four electron groups can lead to shapes like tetrahedral or trigonal pyramidal, depending on the presence of lone pairs.

Molecular Geometry

Molecular geometry describes the three-dimensional arrangement of atoms in a molecule. It is influenced by the number of electron groups and their types (bonding vs. lone pairs). In the case of a central atom with four electron groups and three bonded atoms, the resulting shape is trigonal pyramidal, as one of the groups is a lone pair.