FLUORINE

The fluorine is the chemical element of atomic placed number 9 in the group of the halogens (group 17) of the periodic table of the elements and his symbol it is F.
It is a gas of pale yellow color. In pure form it is highly dangerous, causing serious chemical burns in touch with the skin.
Some fluorides are added to the pasta of teeth for the prevention of caries.
The fluorine (of the Latin fluere, that means "to "flow") forming a part of the mineral fluorita, it was described in 1529 by Georgius Agricola, though finally, in 1886, the French chemist Henri Moissan managed it to isolate.
The fluorine is the most abundant halogen in the terrestrial bark.
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