Chlorine is the second element in Group 17 of the periodic table, a group of elements known as the halogens. Chlorine's atomic number is 17, its atomic mass is 35.453, and its chemical symbol is Cl.

Properties

Chlorine is a greenish yellow poisonous gas with a density of 3.21 grams per liter. Its specific gravity compared to air is 2.49. Chlorine's boiling point is -29.29°F (-34.05°C) and its melting point is -149.8°F (-101°C). The gas is soluble in water and reacts with water as it dissolves.

Chlorine is one of the most active of all elements. It combines with all elements except the noble gases of Group 18 of the periodic table. Chlorine does not undergo combustion, although it does support combustion in much the same way as does oxygen.

Occurrence and Extraction

Chlorine occurs abundantly in the Earth's crust and in the Earth's hydrosphere. Its...