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Fluorine facts for kids

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gas: very pale yellow
liquid: bright yellow
solid: transparent (beta), opaque (alpha)
Some liquid fluorine condensed in liquid nitrogen
Liquid fluorine at very cold temperatures
General properties
Name, symbol, number fluorine, F, 9
Element category halogen
Group, period, block 172, p
Standard atomic weight 18.9984032(5) g/mol
Electron configuration [He] 2s2 2p5
Electrons per shell 2, 7 (Image)
Physical properties
Phase gas
Density (0 °C, 101.325 kPa)
1.696 g/L
Liquid density at b.p. 1.505 g/cm3
Melting point 53.53 K, −219.62 °C, −363.32 °F
Boiling point 85.03 K, −188.12 °C, −306.62 °F
Critical point 144.4 K, 5.215 MPa
Heat of vaporization 6.51 kJ/mol
Specific heat capacity (25 °C) (Cp) (21.1 °C) 825 J·mol−1·K−1
(Cv) (21.1 °C) 610 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 38 44 50 58 69 85
Atomic properties
Oxidation states −1
(oxidizes oxygen)
Electronegativity 3.98 (Pauling scale)
Ionization energies
1st: 1,681 kJ/mol
2nd: 3,374 kJ/mol
3rd: 6,147 kJ/mol
Covalent radius 64 pm
Van der Waals radius 135 pm
Crystal structure cubic
Crystal structure note the structure shows solid fluorine, just under the melting point, 1 atm
Magnetic ordering diamagnetic
Thermal conductivity (300 K) 0.02591 W/(m·K)
CAS registry number 7782-41-4
Most stable isotopes
Main article: Isotopes of fluorine
iso NA half-life DM DE (MeV) DP
18F trace 109.77 min β+ (96.9%) 0.634 18O
ε (3.1%) 1.656 18O
19F 100% 19F is stable with 10 neutrons
A more real picture of fluorine

Fluorine (symbol F) is a chemical element that is very poisonous. Its atomic number (which is the number of protons in it) is 9, and its atomic mass is 19. It is part of the Group 7 (halogens) on the periodic table of elements.


Fluorine is a light yellow diatomic gas. It is very reactive gas, which exists as diatomic molecules. It is actually the most reactive element. Fluorine has a very high attraction for electrons, because it is missing one. This makes it the most powerful oxidizing agent. It can rip electrons from water (making oxygen) and ignite propane on contact. It does not need a spark. Metals can catch on fire when placed in a stream of fluorine. After it is reduced by reacting with other things, it forms the stable fluoride ion. Fluorine is very poisonous. Fluorine bonds very strongly with carbon. It can react with the unreactive noble gases. It explodes when mixed with hydrogen. The melting point of fluorine is -363.33°F (-219.62°C), the boiling point is -306.62°F (-188.12°C).

Chemical compounds

Chemical compounds containing fluorine ions are called fluorides. Fluorine only exists in one oxidation state: -1.


Fluorite crystals 270x444
Fluorite crystals, the "ore" of fluorine

Fluorine is not found as an element on the earth; it is much too reactive. Several fluorides are found in the earth, though. When calcium phosphate is reacted with sulfuric acid to make phosphoric acid, some hydrofluoric acid is produced. Also, fluorite can be reacted with sulfuric acid to make hydrofluoric acid. Is a luiquid of fluoride U. Fluorine naturally occurs on the earths' crust in rocks, coal and clay.


Fluorine is normally made by electrolysis. Hydrogen fluoride is dissolved in potassium fluoride. This mixture is melted and an electric current is passed through it. This is electrolysis. Hydrogen is produced at one side and fluorine at the other side. If the sides are not separated, the cell may explode.

Someone made fluorine in 1986 without using electrolysis. They produced manganese(IV) fluoride by using various chemical compounds, which released fluorine gas.


Fluorine is used to enrich uranium for nuclear weapons. It is also used to make sulfur hexafluoride. Sulfur hexafluoride is used to propel stuff out of an aerosol can. It is also used to make integrated circuits. Fluorine compounds have many uses. Fluoride ions are in fluorine compounds. Fluoride ions can be in toothpaste. Some are used in nonstick coatings. Freons contain fluorine.


Fluorine as an element is extremely reactive and toxic. It can react with almost everything, even glass. Fluorine is also poisonous.

Fluoride ions are somewhat toxic. If too much toothpaste containing fluoride is eaten then fluoride poisoning may occur. Fluoride is not reactive, though.

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