About

Fluorine is a pale yellow, highly corrosive gas, existing as a diatomic molecule (F₂). It is the most electronegative and reactive of all elements, capable of forming compounds with noble gases. It's a key component of many plastics, such as Teflon, and is widely added as fluoride to toothpaste and public water supplies to prevent tooth decay. Handling pure fluorine is extremely dangerous.

Atomic Properties

Atomic Number9

Atomic Weight18.998 u

Neutrons (common)10

Electron Configuration[He] 2s² 2p⁵

Full Configuration1s² 2s² 2p⁵

Electrons per Shell2, 7

Electronegativity3.98

Electron Affinity328 kJ/mol

Oxidation States-1

Covalent Radius60 pm

Van der Waals Radius147 pm

Ionic Radius133 pm

Periodic Table Position

Group17

Period2

BlockP

Chemical SeriesHalogens

Physical Properties

State at STPgas

AppearancePale yellow-green gas

Crystal Structuremonoclinic

Magnetic Orderingdiamagnetic

Thermal Properties

Melting Point53.53 K

Boiling Point85.03 K

Triple Point53.48 K

Thermal Conductivity0.028 W/(m·K)

Specific Heat0.824 J/(g·K)

Molar Heat31.304 J/(mol·K)

Heat of Fusion0.51 kJ/mol

Heat of Vaporization6.62 kJ/mol

Abundance

In Earth's Crust585 ppm

In Ocean1.3 ppm

In Solar System0.4 ppm

In Human Body37 ppm

In Universe0.4 ppm

Discovery

Discovered byHenri Moissan

Discovery Year1,886

Occurrenceprimordial

CAS Number7782-41-4

Electron Configuration

Energy

↿⇂

↿

Isotopes of Fluorine

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
¹⁸F	18.000938	—	109.734 m	Positron Emission
¹⁹F	18.998403	100%	Stable	Stable

Interactive Visualization

Explore the 3D Bohr model of Fluorine in our interactive viewer.

View 3D Model of Fluorine