ELEMENTLE

Element 3 · Alkali Metal

Lithium

Period 2 · Group 1

Lithium (from Greek:λίθος lithos, "stone") is a chemical element with the symbol Li and atomic number 3. It is a soft, silver-white metal belonging to the alkali metal group of chemical elements. Under standard conditions it is the lightest metal and the least dense solid element.

Three reasons Lithium stands out

  1. 1

    Used in rechargeable batteries.

  2. 2

    It is the lightest of all metals and can actually float on water.

  3. 3

    Used as a mood-stabilising medication to treat bipolar disorder.

From ancient brines to modern batteries

Lithium is the lightest metal, soft enough to cut yet chemically eager to surrender an electron. That electron movement makes lithium compounds valuable in rechargeable cells. The element also travels through a very different world: carefully measured lithium salts have long been used in psychiatric medicine.

Lithium at a glance
Atomic number / protons3
SymbolLi
Family (Elementle)Alkali Metal
Classification (PubChem)Alkali metal
Period2
Group1
Atomic mass (u)7.0
Standard stateSolid
Electron configuration[He]2s1
Reported oxidation states+1
Electronegativity (Pauling)0.98
Atomic radius (pm)182
First ionization energy (eV)5.392
Electron affinity (eV)0.618
Density (g/cm³)0.534
Melting point453.65 K (180.5 °C)
Boiling point1615 K (1,341.85 °C)
Discovery (PubChem)1817

Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.

Sources & further reading

PubChem: Lithium · Lithium on Wikipedia

The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.