Fluorine (F) – element 9
Fluorine is a chemical element with the symbol F and atomic number 9. It is a reactive nonmetal in group 17 (halogens), period 2 of the periodic table (p-block), and is a gas at room temperature.
Fluorine (F) has atomic number 9, atomic mass 18.998 u and electron configuration [He] 2s2 2p5.
Fluorine facts
| Symbol | F |
|---|---|
| Atomic number | 9 |
| Atomic mass | 18.998 u (g/mol) |
| Category | reactive nonmetal |
| Group | group 17 (halogens) |
| Period | 2 |
| Block | p-block |
| Phase at 20 °C | Gas |
| Electron configuration | 1s2 2s2 2p5 |
| Noble-gas notation | [He] 2s2 2p5 |
| Electrons per shell | 2, 7 |
| Valence electrons | 7 |
Bohr model and shells
Fluorine has 9 electrons in 2 shells: 2, 7. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 53.48 K (-219.7 °C) |
|---|---|
| Boiling point | 85.03 K (-188.1 °C) |
| Density | 1.696 g/L |
| Electronegativity (Pauling) | 3.98 |
| Electron affinity | 328.165 kJ/mol |
| Ionization energies | 1681, 3374.2, 6050.4 kJ/mol (1st, 2nd, 3rd) |
| Discovered by | André-Marie Ampère |
Use the atomic mass in the molar mass calculator for any formula containing F.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of fluorine?
The atomic mass of fluorine is 18.998 u, so one mole of fluorine atoms weighs 18.998 g.
What is the electron configuration of fluorine?
Fluorine has 9 electrons: 1s² 2s² 2p⁵, or [He] 2s² 2p⁵ in noble-gas notation. Electrons per shell: 2, 7.
How many valence electrons does fluorine have?
Fluorine has 7 valence electrons (group 17).
Is fluorine a metal?
No. Fluorine is a nonmetal (reactive nonmetal).
Where is fluorine on the periodic table?
Fluorine is in group 17 (halogens), period 2, in the p-block.
Data: Periodic-Table-JSON (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.