Fluorine
The most electronegative and reactive of all elements.
Inside the Fluorine atom
Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Fluorine atom step by step.
Electron configuration
[He] 2s2 2p5
A neutral Fluorine atom has 9 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.
Shell distribution
Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.
Physical & atomic properties
- State (room temp)
- Gas
- Melting point
- 53 K (-220 °C)
- Boiling point
- 85 K (-188 °C)
- Density
- 0.001696 g/cm³
- Electronegativity
- 3.98 Pauling
- Atomic radius
- 50 pm
- 1st ionization energy
- 1681 kJ/mol
- Category
- Reactive nonmetals
Discovery & naming
- Discovered
- 1886
- Discovered by
- Henri Moissan
- Origin of name
- Latin 'fluere', meaning to flow.
Notable uses
Toothpaste, refrigerants, and non-stick Teflon coatings.
Where Fluorine comes from
Stellar fusion and dying stars
Fragile and easily destroyed. Several stellar pathways contribute, in proportions still being worked out.
Simplified origin map — many elements form through more than one astrophysical pathway.
Summary
- Atomic number
- 9
- Atomic mass
- 18.998
- Category
- Reactive nonmetals
- Group · Period
- 17 · 2
- Block
- p-block
- Shells
- 2 · 7