Catalyst - a substance which alters the rate of a reaction without itself undergoing any permanent chemical changes

Electromagnetic radiation - a form of radiant energy released by certain electromagnetic processes such as visible light and infrared

Haber process - an artificial nitrogen fixation process and is the main industrial procedure for the production of ammonia

Radioactive isotope - isotope with an unstable nucleus that will undergo radioactive decay to release excess energy

Trace element - small amount elements that human needs

Transition metal - elements between Groups II and III of the periodic table