Which process involves breaking a covalent bond such that each atom takes one of the shared electrons?

Homolysis is the process that involves breaking a covalent bond in such a way that each atom involved in the bond retains one of the shared electrons. This results in the formation of two radicals, where each radical has an unpaired electron. This process is important in various chemical reactions, particularly in radical chemistry, where species with unpaired electrons can initiate chain reactions.

In this scenario, when a covalent bond undergoes homolysis, the bond is split symmetrically, with each atom receiving one electron, making it a significant mechanism in many organic reactions where radical intermediates are formed.

The other processes mentioned do not fit this definition. Heterolysis, for example, involves the breaking of a bond in a way that one atom takes both electrons from the bond, resulting in the formation of charged species. Polarization refers to the distortion of the electron cloud within a covalent bond in response to an external electric field or the presence of another polar molecule. Ionization involves the complete removal of an electron from an atom or molecule, resulting in the formation of ions. Therefore, homolysis is the correct process when describing the splitting of a covalent bond into two radicals.