9Gas
F 18.998 Atomic mass · uHalogens
Fluorine
Fluorine is a chemical element with symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. As the most electronegative element, it is extremely reactive:almost all other elements, including some noble gases, form compounds with fluorine.
Discovery 1670 (André-Marie Ampère)
K2L7
Physical properties
Values for the element in its standard state.
- Density
- 0.001696g/cm³
- Melting point
- 54K
- Boiling point
- 85K
- Atomic radius
- 71pm
- Bonding type
- Atomic
- Molar heat
- Not available
Inside the atom
Electron arrangement and the energy behind its behavior.
Full electron configuration
1s, 2 electrons; 2s, 2 electrons; 2p, 5 electrons;
[He] represents 2 core electrons. The full view shows them explicitly.
9 electrons Orbital order preserved from source
- Electronegativity
- 3.98Pauling scale
- First ionization energy
- 1,681kJ/mol
- Electron affinity
- 328kJ/mol
- Van der Waals radius
- 147pm
F FluorineAtomic number 9
1,681kJ/mol
Atomic numberGaps indicate unavailable data
About fluorine
- Appearance
- Not recorded
- Discovery
- 1670 (André-Marie Ampère)
- Data source
- Read the reference
A missing value means it is unavailable in this reference dataset. Values can vary with measurement method and conditions.