Britannica
Sources used in this answer
How do atoms, electrons, ions, and free radicals participate in chemical reaction mechanisms?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
reaction mechanism
Possible energy diagram for the dissociation of a covalent molecule, E–N, into its ions E+ and N− (see text).
In chemical reaction mechanisms, atoms, electrons, ions, and free radicals act as the fundamental components that undergo transformation as substances are converted into products. These processes involve the breaking and reforming of chemical bonds, which requires shifts in the arrangement of electrons and changes in the relative positions of atoms within and among molecules.12
- Atoms and Electrons: Reactions involve the shuffling and reassembly of atoms. Because only valence electrons typically participate in bond formation, their movement and sharing are central to defining the reaction path.324
- Ions: These are atoms or groups of atoms bearing electrical charges. They participate in mechanisms through processes such as electron transfer or by acting as bridging groups that facilitate bond rearrangement, as seen in certain oxidation-reduction reactions.56
- Free Radicals: These are highly reactive, short-lived species that act as transient intermediates. They often participate in chain reactions, where they are consumed in one step and regenerated in another, allowing a single radical to drive the production of many molecules.7
Understanding how these species interact allows chemists to control reaction paths, favoring desired products while minimizing waste.12