Which of the following best describes homolytic fission?

Homolytic fission describes a specific way in which a covalent bond can break. In this process, the bond breaks evenly, resulting in two atoms, each taking one of the shared electrons that were previously involved in the bond. This results in the formation of two radicals, each with an unpaired electron.

By retaining one of the shared electrons, each atom becomes a neutral radical species, which is significant in various chemical reactions, particularly in radical mechanisms. The existence of these radicals can lead to further reactions, such as chain reactions in organic chemistry.

The other options do not correctly describe homolytic fission. For instance, the idea that covalent bonds break unevenly does not apply here, as that would refer to heterolytic fission. The complete ionization of atoms implies a different type of bond breaking, and stating that covalent bonds remain intact contradicts the definition of fission altogether. Therefore, the description of homolytic fission is accurately represented as each atom retaining one of the shared electrons equally.