NAME: derived from the Greek word “khlôros” meaning pale green.
DISCOVERY: 1774 by C.W. Scheele in Uppsala, Sweden.
DESCRIPTION: a greenish yellow, dense gas with a sharp, pungent smell.
SOURCE: Chlorine is not found free in nature, but combined chiefly with sodium chloride in common salt and the minerals carnallite and sodium chloride.
USES: Chlorine is used to produce safe drinking water and many consumer products such as paper, dyestuffs, textiles, petroleum products, medicines, antiseptics, insecticides, foodstuffs, solvents, paints, and plastics. It is also used to produce chlorates, chloroform, carbon tetrachloride and bromine. A further substantial use for this element is in organic chemistry, both as an oxidizing agent and in substitution reactions.
BIOLOGICAL ROLE: The chloride ion is essential to life. Chlorine gas is a respiratory irritant, which can be fatal after a few deep breaths. It was used as a weapon in World War II. Chlorine liquid burns the skin.
ATOMIC NUMBER: 17
ATOMIC SYMBOL: Cl
ATOMIC MASS: 35. 4527 amu
MELTING POINT: -100.98°C (172.17°K, -149.765°F)
BOILING POINT: -34.6°C (238.55°K, -30.279997°C)
NUMBER OF NEUTRONS: 18
CRYSTAL STRUCTURE: orthorhombic
DENSITY @ 293K: 3.214 g/cm³