Fluorine
A poisonous pale yellow gaseous element belonging to group 17 of the periodic table (The halogens). It is the most chemically reactive and electronegative element. It is highly dangerous, causing severe chemical burns on contact with flesh. Fluorine was identified by Scheele in 1771 and first isolated by Moissan in 1886.
Gallery
Fulvio314, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
Physical Propertiesmass · density · phase · crystal
Atomic Mass
18.9984Da
Density
0.0016g/L
Phase (STP)
Gas
Melting Point
53.5K
Boiling Point
85.0K
Molar Heat
0.8240J/(mol·K)
Crystal Structure
MCL
Atomic Radiiatomic · covalent · van der Waals
Atomic (Empirical)
50.00pm
Covalent
64.00pm
Van der Waals
147.00pm
Electronic Propertieselectronegativity · ionization · affinity
Electron Configuration
[He] 2s2 2p5
Electron Shells
2, 7
Electronegativity
3.98Pauling
Electron Affinity
3.4kJ/mol
1st Ionization Energy
17.4kJ/mol
Oxidation States
-1
Orbital DiagramAufbau · Hund's rule · Pauli exclusion
Full: 1s2 2s2 2p5Short: [He] 2s2 2p5
Ionization Energies (9 known)
Emission Spectrumvisible range · characteristic spectral lines
Abundanceby mass
Log scale · ppm = parts per million by mass
Biological Role
Strengthens tooth enamel as fluorapatite. Excess causes fluorosis.
Discovery
Discovered By
Henri Moissan
Named By
—
Year
1886
Nuclear Data
Known Isotopes
19
Stable Isotopes
3
Stable Mass Numbers
13, 19, 30
Natural isotopic abundance (IUPAC recommended values)
Isotopes of F19 known
| Nuclide | Z | N | Mass (AMU) | Half-life | Decay | Jπ | Abundance |
|---|---|---|---|---|---|---|---|
| 13Fstable | 9 | 4 | 13.045121 | Stable | p | 1/2+ | — |
| 14F | 9 | 5 | 14.034315 | Unknown | p | 2- | — |
| 15F | 9 | 6 | 15.017785 | 1.10 zs | p (1%) | 1/2+ | — |
| 19Fstable | 9 | 10 | 18.998403 | Stable | stable (1%) | 1/2+ | 10000.0000% |
| 29F | 9 | 20 | 29.043103 | 2.50 ms | β⁻ (1%), β⁻n (0.6%), 2n | 5/2+ | — |
| 30Fstable | 9 | 21 | 30.052561 | Stable | n | — | — |
| 31F | 9 | 22 | 31.061023 | Unknown | β⁻, β⁻n, 2n | 5/2+ | — |