ELEMENTARY REACTION STEP

"Chemical reactions usually take place in a number of simple (""elementary"") reaction steps proceeding in series. The overall reaction is the sum of the elementary reactions. E.g., the electroplating of copper on some metal involves three elementary steps: (1) a redox reaction in which the double positively charged copper cation reacts with an electron from the metal electrode to form a single charged copper ion, followed by (2) a metal deposition reaction in which the single charged copper ion reacts with a second electron to form a copper atom on the surface of the metal, and finally (3) an electrocrystallization step in which the copper atom becomes incorporated into the crystalline structure of the underlying metal. The rate-determining step in copper deposition is usually the first of these steps. "