17Cl Chlorine

Year Discovered


Discovered By

Karl Scheele of Sweden

Biological Rating

Necessary for all life.


Named from the Greek word meaning “pale green,” chlorine is a corrosive, yellowish-greenish gas. Chlorine is a heavily used industrial element. Over twenty billion pounds are produced in the United States annually. It is used in many applications, such as in bleaches (where Clorox gets its name), as a sterilizing agent for water supplies, and as an extractor of metals from ores or compounds. It is essential in the production of solvents, paper products, dyes, textiles, medicines, insecticides, paints, refrigerants and plastics, particularly the plastic polyvinyl chloride (PVC).

Biological Benefits

Chlorine salts are critical for many species, including humans. Its ion is used as an electrolyte, as well as making the hydrochloric acid the stomach uses for digestion.

Role in Life Processes

Critical for life processes in plants and animals.

Percentage Amount in the Human Body: 0.14%


Chlorine is obtained by the electrolysis of sodium chloride solutions. Along with sodium, chlorine is abundant in the oceans. Chlorine is present in small amounts in many minerals. The most common chlorine-bearing mineral is, of course, halite (sodium chloride). Halite salt is mined in the USA, China, Germany, Russia and Canada.