A Level Chemistry OCR Practice Exam

What defines homolytic fission?

1. The breaking of a covalent bond where both electrons remain with the original atom.

2. The cleavage of a bond producing two ions of opposite charge.

3. The breaking of a covalent bond with one electron going to each atom, forming two radicals.

4. A process of creating covalent bonds between atoms.

The correct answer is: The breaking of a covalent bond with one electron going to each atom, forming two radicals.

Homolytic fission is characterized by the breaking of a covalent bond in such a manner that each atom involved in the bond retains one of the shared electrons, resulting in the formation of two uncharged species known as radicals. These radicals each have an unpaired electron, making them highly reactive. This process is important in various chemical reactions, particularly in organic and polymer chemistry, because it leads to the generation of reactive intermediates that can participate in subsequent reactions. The other options reflect different types of fission or bonding processes that do not accurately depict homolytic fission. For instance, the first option refers to a scenario where both electrons stay with one atom, which describes heterolytic fission rather than homolytic. The second option discusses ion formation, which is also not relevant to homolytic fission as it results in charged species, whereas homolytic fission yields neutral radicals. Lastly, the fourth option pertains to bond formation rather than bond cleavage, which is the focus of homolytic fission.