17
Chlorine
Atomic Number17
Atomic Mass35.453 u
CategoryHalogen
State at Room TempGas
Year Discovered1774
About Chlorine
Yellow-green gas with a choking smell. Used to purify drinking water worldwide, saving millions of lives. Combined with sodium makes table salt. PVC plastic is made from chlorine. Used in swimming pools, bleach, and disinfectants. Was used as a chemical weapon in World War I. The name comes from the Greek word for pale green.
More Halogens
9
Fluorine
The most reactive and electronegative element. Reacts with almost every other el...
35
Bromine
One of only two elements liquid at room temperature, the other being mercury. Re...
53
Iodine
Essential for thyroid hormone production. Iodine deficiency causes goiter and is...
85
Astatine
The rarest naturally occurring element on Earth. At any moment the entire planet...