About

Lithium is a soft, silvery-white alkali metal. It is the lightest metal and the least dense solid element, so light it can float on oil. Highly reactive and flammable, it is primarily used in rechargeable batteries that power everything from mobile phones and laptops to electric vehicles. It's also used in high-temperature lubricants and mood-stabilizing medications.

Atomic Properties

Atomic Number3

Atomic Weight6.94 u

Neutrons (common)4

Electron Configuration[He] 2s¹

Full Configuration1s² 2s¹

Electrons per Shell2, 1

Electronegativity0.98

Electron Affinity59.6 kJ/mol

Oxidation States+1

Covalent Radius128 pm

Van der Waals Radius182 pm

Ionic Radius76 pm

Periodic Table Position

Group1

Period2

BlockS

Chemical SeriesAlkali metals

Physical Properties

State at STPsolid

AppearanceSilvery-white metal, which tarnishes quickly to a dull gray.

Crystal Structurebcc

Magnetic Orderingparamagnetic

Speed of Sound6,000 m/s

Thermal Properties

Melting Point453.65 K

Boiling Point1,615 K

Triple Point453.6 K

Thermal Expansion0 1/K

Thermal Conductivity84.8 W/(m·K)

Specific Heat3.582 J/(g·K)

Molar Heat24.86 J/(mol·K)

Heat of Fusion3 kJ/mol

Heat of Vaporization145.92 kJ/mol

Abundance

In Earth's Crust20 ppm

In Ocean0.18 ppm

In Solar System0.002 ppm

In Human Body0.03 ppm

In Universe0.006 ppm

Discovery

Discovered byJohan August Arfwedson

Discovery Year1,817

Occurrenceprimordial

CAS Number7439-93-2

Electron Configuration

Energy

↿⇂

↿

Isotopes of Lithium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
⁶Li	6.015122	7.59%	Stable	Stable
⁷Li	7.016004	92.41%	Stable	Stable
⁸Li	8.022487	—	838.7 ms	Beta Minus Decay, Alpha Decay

Interactive Visualization

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

View 3D Model of Lithium