Question

(a) How does one determine the number of electron domains in a molecule or ion? (b) What is the difference between a bonding electron domain and a nonbonding electron domain?

Short answer

(a) To determine the number of electron domains in a molecule or ion, first draw the Lewis structure, then identify and count the single bonds, multiple bonds (double and triple bonds), and lone pairs of electrons surrounding the central atom(s). The sum of these values gives the total number of electron domains. (b) Bonding electron domains are regions where electrons are shared between two atoms, forming a chemical bond (single, double, or triple bonds). Nonbonding electron domains are regions with lone pairs of electrons that do not participate in bonding. Both types of electron domains affect the shape and properties of the molecule or ion.

Step-by-step solution

(a) Determining the Number of Electron Domains

Electron domains are regions in a molecule or ion where electrons are most likely to be found. They can be either bonding or nonbonding electron domains. To determine the number of electron domains in a molecule or ion, follow these steps: 1. Draw the Lewis structure of the molecule or ion. 2. Identify and count the number of single bonds, multiple bonds (double and triple bonds), and lone pairs of electrons surrounding the central atom(s). 3. The sum of these values will give you the total number of electron domains in the molecule or ion. Remember that in the case of polyatomic ions, you should also consider the formal charge on the ion to determine the correct Lewis structure and electron domains.

(b) Bonding vs. Nonbonding Electron Domains

Bonding electron domains and nonbonding electron domains are two types of electron domains that can be found in a molecule or ion. - Bonding electron domains: These are regions where electrons are shared between two atoms, forming a chemical bond. They can be either single bonds, double bonds, or triple bonds. In all cases, they involve the overlap of atomic orbitals, which leads to the formation of molecular orbitals and the sharing of electrons between atoms. The number of bonding electron domains corresponds to the number of bonds involving the central atom(s). - Nonbonding electron domains: These are regions where electrons are not involved in bonding between atoms. They are also known as lone pairs of electrons. Lone pairs are pairs of valence electrons that do not participate in the formation of a chemical bond. They can affect the shape and polarity of a molecule, as they can cause repulsion between electron domains, resulting in changes to the molecular geometry. The number of nonbonding electron domains corresponds to the number of lone pairs surrounding the central atom(s). To sum up, bonding electron domains involve shared electrons between atoms forming chemical bonds, while nonbonding electron domains involve lone pairs of electrons that do not participate in bonding. Both types of electron domains contribute to the overall electron domain count and affect the shape and properties of the molecule or ion.