Key information
Atomic number: 
53
Atomic weight: 
126.9
Density: 
4940 kg/m³
Boiling point: 
456.16° K
Melting point: 
386.86° K
Heat vapour: 
21.78 kJ/mol
Heat fusion: 
7.83 kJ/mol
Group: 
Halogen Elements

Iodine was discovered within seaweed ash (kelp) by the French chemist Bernard Courtois. In October 1813 the British chemist Humphry Davy (1778 -1829) and his wife, accompanied by Michael Faraday as his scientific assistant traveled to France. Whilst in Paris Davy was asked to investigate the substance isolated by Courtois. Davy showed it to be an element, and it was given the name Iodine. The name is from the Greek iodides for violet. Iodine crystals give off, when heated, a violet vapour with an irritating odour.

Electron Shell: 
Amazon Books
Image of The Last Sorcerers: The Path from Alchemy to the Periodic Table
Author: National Academy of Sciences, Richard Morris
Publisher: Henry (Joseph) Press (2003)
Binding: Hardcover, 294 pages