Halogens
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
Fluorine
Fluorine was named after the mineral fluorspar it was found in. It was one of the last common elements to be isolated. It took scientists 70 years to extract it because it is so reactive. Henri Moissan figured out how to produce fluorine in 1886. Fluorine is one of the most dangerous chemicals. Fluorine is used in nuclear weapons, welding, nuclear power, solvents, high temperature plastics such as Teflon, and frosting glasses.
Chlorine
Chlorine was found by Carl Scheele in 1770. It is found most abundantly in sodium chloride. It is obtained from seawater and underground deposits of rock. To chlorine you must pass electrical current through a water solution of sodium chloride. Chlorine gas is toxic. Chlorine is used in disinfectant in watering systems, swimming pools, and water treatment plants. Chlorine compounds can be found in pesticides, herbicides, and fungicides.
Bromine
Bromine was discovered in 1826 by Antoine-Jerome Balard. Bromine is a brownish yellow in liquid form that vaporizes easily. It can be obtained the same way chlorine is. It can be found in sea water and in Earth's crust. Bromine can be used in disinfectants. Compounds of bromine can be used in leaded gasoline, photographic film, and pesticides.
Iodine
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
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.