Halogen Facts



  • Halogens are the chemical elements fluorine, chlorine, bromine, iodine.
  • Halogen lights floodlight a stadium at night, allowing large audiences to watch. Halogens are and astatine. non-metals and make up part of the seventh main Group in the Periodic Table.
  • The word ‘halogen’ means salt-forming. All halogens easily form salt compounds.
  • Many of the salts in the sea are compounds of a halogen and a metal, such as sodium chloride and magnesium chloride.
  • The halogens all have a strong, often nasty, smell.
  • Fluorine is a pale yellow gas, chlorine a greenish gas, bromine a red liquid, and iodine a black solid.
  • Astatine is an unstable element that survives by itself only briefly. It is usually made artificially.
  • Chlorine salts are often added to the water in swimming pools to kill bacteria, giving the water a greenish-blue tinge.
  • The halogens together form Group 7 of the Periodic Table, elements with 7 electrons in the outer shells.
  • Because halogens have one electron missing, they form negative ions and are highly reactive.
  • The iodine and bromine in a halogen lightbulb make it burn brighter and longer than a normal electric lightbulb.
  • Fluorides (fluorine compounds) are often added to drinking water to prevent tooth decay.