Fluorine - F

Atomic number

9

Atomic mass

18.998403 g.mol ^-1

Electronegativity according to Pauling

4

Density

1.8*10^-3 g.cm^-3 at 20°C

Melting point

-219.6 °C

Boiling point

-188 °C

Vanderwaals radius

0.135 nm

Ionic radius

0.136 nm (-1) ; 0.007 (+7)

Isotopes

2

Electronic shell

[ He ] 2s²2p⁵

Energy of first ionisation

1680.6 kJ.mol ^-1

Energy of second ionisation

3134 kJ.mol ^-1

Energy of third ionisation

6050 kJ mol^-1

Standard potential

- 2.87 V

Discovered by

Moissan in 1886

Small amounts of fluorine are naturally present in water, air, plants and animals. As a result humans are exposed to fluorine through food and drinking water and by breathing air. Fluorine can be found in any kind of food in relatively small quantities. Large quantities of fluorine can be found in tea and shellfish.

Fluorine is essential for the maintenance of solidity of our bones. Fluorine can also protect us from dental decay, if it is applied through toothpaste twice a day. If fluorine is absorbed too frequently, it can cause teeth decay, osteoporosis and harm to kidneys, bones, nerves and muscles.

Fluorine gas is released in the industries. This gas is very dangerous, as it can cause death at very high concentrations. At low concentrations it causes eye and nose irritations.

When fluorine from the air ends up in water it will settle into the sediment. When it ends up in soils, fluorine will become strongly attached to soil particles. In the environment fluorine cannot be destroyed; it can only change form.

Fluorine that is located in soils may accumulate in plants. The amount of uptake by plants depends upon the type of plant and the type of soil and the amount and type of fluorine found in the soil. With plants that are sensitive for fluorine exposure even low concentrations of fluorine can cause leave damage and a decline in growth. Too much fluoride, wheater taken in form the soil by roots, or asdorbed from the atmosphere by the leaves, retards the growth of plants and reduces crop yields. Those more affected are corns and apricots.

Animals that eat fluorine-containing plants may accumulate large amounts of fluorine in their bodies. Fluorine primarily accumulates in bones. Consequently, animals that are exposed to high concentrations of fluorine suffer from dental decay and bone degradation. Too much fluorine can also cause the uptake of food from the paunch to decline and it can disturb the development of claws. Finally, it can cause low birth-weights.