By: Ellie Allen

What are Halogens?

Halogens are in group 17 on the periodic table. The word halogen means salt-former. Compounds containing halogens are called salts. All of the Halogens have seven electrons in their outer energy level. Halogens exist in three forms of matter solid, liquid, and gas.

Uses of Halogens and Where They Are Found


Iodine was found in 1811 by Bernard Courtois. It was named after the Greek word iodos which means violet by Humphry Davy. Iodine is obtained from sea water. Iodine is toxic if it is ingested. Iodine is the least active of the common halogens. Iodine is used in dyes, specialized soaps, lubricants, photographic film, medicines, and pharmaceuticals.


Astatine is one of the rarest of the naturally occurring elements. It can be found in Earth's crust in very minimal amounts. In 1940 D.R. Corson, K.R. Mackenzie, and Emilio Segre made the element astatine. Astatine is highly radioactive. There are no known uses for astatine other than research purposes.