|Atomic mass||19.0 amu|
|Date of discovery||1886|
|Name of discoverer||Joseph Henri Moissan|
|Name origin||From the Latin word fluo (flow)|
|Obtained from||Mineral fluorite|
Fluorine is the lightest member of the halogen elements, or Group VIIa of the periodic table. It is also the most reactive chemical element. Fluorine is so dangerous that it must be stored in steel containers, and even then it reacts with the steel. Fortunately, the layer of fluoride rust that forms is unreactive, and prevents it from reacting further. Fluorine is a component of many drugs, and its radioisotope is used in functional brain imaging and bone scans. Under ordinary conditions, pure fluorine is a gas with a pale yellow color. 
The element is used in producing isotopically fractionated uranium from uranium hexafluoride (UF6). Hydrofluoric acid (HF) is extensively used for etching the glass of light bulbs, and other glass products. An ion of fluorine, Fluoride, is also added to dental health products is hopes that it will bond with the calcium in teeth. That is thought to help strengthen the teeth against acid decay.
|Periodic Table of the Elements|