What is a halogen

• A halogen is a highly reactive element found in Group VIIA the periodic table of elements. The halogens found in chemical compounds are fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).
  
  

Halogen-containing compounds

• A chemical compound is a substance made of molecules (connected atoms) of more than one element. Any molecule that includes a halogen can be called a halogen-containing compound.
  
  

Halides (halogen salts)

• Salt pools containing naturally occurring halides.Image by Flickr.com, courtesy of Alisha Vargas
  
  A halide, or halogen salt, is a substance made of halogen ions (halogen atoms with extra electrons and a net charge of -1) and positively charged ions (cations). Halides can be formed with metals and most non-metals.
  
  

Halogen acids (hydrogen halides)

• A hydrogen ion combined with a halogen ion forms a hydrogen halide. When dissolved in water, a hydrogen halide becomes a type of acid called a hydrohalic acid; these are very strong due to the high reactivity of halogens.
  
  

Organic halogen compounds

• Many medications are organic halogen compounds.Image by Flickr.com, courtesy of psyberartist
  
  An organic compound is a compound made of chains and/or rings of carbon atoms linked by covalent bonds. Halogens are found in many organic compounds, typically replacing a hydrogen atom. Unlike other halogen-containing compounds, the halogen atoms are not ions in organic halogen compounds.