The term activation energy is best described as the minimum kinetic energy that particles must possess for a chemical reaction to occur. This energy is required to break the existing bonds in the reactants and form new bonds in the products. It acts as a barrier that must be overcome for the reaction to proceed.
In simpler terms, activation energy is the energy needed to start a chemical reaction. Without this energy, the reactants would not have enough energy to collide effectively and transform into products. This concept is crucial in understanding how reactions occur and why some reactions require heat or a catalyst to proceed.