Name Chlorine
Symbol Cl
Atomic Number 17
Atomic Mass 35.453 atomic mass units
Number of Protons 17
Number of Neutrons 18
Number of Electrons 17
Melting Point -100.98 C
Boiling Point -34.6 C
Density 3.214 grams per cubic centimeter
Normal Phase Gas
Family Halogen
Period 3
Cost 15 cents per 100 grams



Origin of Name From the Greek word khloros, meaning pale green
Date and Place of Discovery 1774 in Uppsala, Sweden
Discovered by Carl Wilhelm Scheele
Common Compounds
Interesting facts
  • It was discovered in 1774 but it wasn't until 1810 that Sir Humphry Davy determined it to be an element.
  • It is not a found freely in nature but is derived from salt.
  • It is a toxic gas which will irritate the respiratory system.
  • In World War I, it was used as an agent to kill.
Common Uses
  • Water purification
  • Paper
  • Textiles
  • Petroleum products
  • Medicines
  • Antiseptics
  • Insecticides
  • Solvents and paints
  • Plastics
  • Bleaches for fabrics, wood and paper
  • Disinfectants
  • Extraction of gold from its ores


Photo Courtesy of
Chemical Elements

Chlorine Atomic Structure Elements by Name Elements by Number Home