Study of Matter Compounds  Elmhurst College
Atoms Physical Properties Mixtures  Chemistry Department
Elements Chemical Properties    Virtual ChemBook


 Chlorine, Cl

Chlorine has the symbol Cl.

From the Greek word "chloros" meaning "pale green"

Discovered by Carl William Scheele Sweden in 1774.

Atomic Number = 17, Atomic Mass = 35.45, 17 protons, 17 electrons, 18 neutrons.

First isolated by

Most common use: Most chlorine is used in the manufacture of chlorinated cleaning compounds, pulp bleaching, disinfectants, and textile processing , bleach, water disinfection, PVC pipe used to provide safe drinking water.

The most common compound of chlorine is common salt, NaCl. In the laboratory the most common form is hydrochloric acid - also found in toilet bowl cleaner. In the house the most common use of chlorine is bleach.

Physical Properties:

Chlorine is a greenish yellow gas which combines directly with nearly all elements. Chlorine is a respiratory irritant. The gas irritates the mucous membranes and the liquid burns the skin. As little as 3.5 ppm can be detected as an odor, and 1000 ppm is likely to be fatal after a few deep breaths. It was used as a war gas in 1915. It is not found in a free state in nature, but is found commonly as NaCl (solid or seawater).

Chemical Properties:

Chlorine, Cl2, reacts with water to produce hypochlorite, OCl-. The position of the equilibrium depends very much upon the pH of the solution.