9
Fluorine
Atomic Number9
Atomic Mass18.998 u
CategoryHalogen
State at Room TempGas
Year Discovered1886
About Fluorine
The most reactive and electronegative element. Reacts with almost every other element including noble gases. Teflon is made from fluorine and carbon. Added to drinking water and toothpaste to prevent tooth decay. Hydrofluoric acid can dissolve glass. Chlorofluorocarbons containing fluorine damaged the ozone layer.
More Halogens
17
Chlorine
Yellow-green gas with a choking smell. Used to purify drinking water worldwide, ...
35
Bromine
One of only two elements liquid at room temperature, the other being mercury. Re...
53
Iodine
Essential for thyroid hormone production. Iodine deficiency causes goiter and is...
85
Astatine
The rarest naturally occurring element on Earth. At any moment the entire planet...