Page 53 - Curriculum Visions Dynamic Book

Fluorine (F)
Element 9. Fluorine is the lightest halogen in group 7 in the Periodic Table.
Fluorine, a pale-yellow, very corrosive gas that is slightly heavier than air, is
the most reactive chemical element in existence.
Fluorine combines with all other elements except helium, neon and argon.
Key facts...
Name: fluorine
Symbol: F
Atomic number: 9
Atomic weight: 18.99
Position in Periodic Table: group 7 (17),
(halogens); period 2
State at room temperature: gas
Colour: pale-yellow
Density of gas at 20°C: 1.58 g/cc
Melting point: –219°C
Boiling point: –188°C
Origin of name: from the Latin word fluere,
meaning to flow
Shell pattern of electrons: 2–7
It is an extremely poisonous gas.
Discovery
French chemist Henri Moissan discovered fluorine in 1886. Because it is so reactive and difficult to isolate, he eventually had
to use an apparatus made from platinum. His success gained him the Nobel Prize for chemistry in 1906.
Technology
It goes into many fluoride-containing plastics. Hydrofluoric acid is used for etching the glass of light bulbs. Fluorochloro- hydrocarbons are used in air
conditioning and in refrigeration.
Fluorides are put into water supplies
to help prevent tooth decay.
Geology
It is never found as a native element, but mainly as the mineral fluorite, calcium fluoride (CaF2), also known as fluorspar and Bohemian emerald.
Biology
Fluorine is found in bones and teeth. Adding fluoride to water has become popular because it helps teeth resist decay.
Fluorite is purple.
For more on fluorine, see Volume 14: Chlorine, Fluorine, Bromine and Iodine in the Elements set.
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