ElementsWhat is lithium?
Lithium is the lightest metal. It is soft enough to cut with a knife and light enough to float on water, with which it reacts. It is taken from salt lakes and from hard rock mines.
What is lithium used for?
Rechargeable batteries for phones, laptops and electric vehicles, heat-resistant glass and ceramics, and light alloys for aircraft.
Where the name comes from
From the Greek word lithos, stone, because it was found in a mineral.
Key facts
- Symbol
- Li
- Atomic number
- 3
- Atomic mass
- 7.0 u
- Family
- Alkali metal
- Period
- 2
- Group
- 1
- Block
- s
- State at room temperature
- Solid
- Melting point
- 180.5 °C (453.65 K, 357 °F)
- Boiling point
- 1,342 °C (1,615 K, 2,447 °F)
- Density
- 0.53 g/cm³
- Electrons per shell
- 2, 1
- Electron configuration
- [He]2s1
- Common oxidation states
- +1
- Electronegativity (Pauling)
- 0.98
- First ionisation energy
- 5.392 eV
- Electron affinity
- 0.618 eV
- Atomic radius (van der Waals)
- 182 pm
- Discovered
- 1817
Place in the periodic table
Lithium is element number 3. It sits in period 2 (row 2) of the periodic table, in group 1 (column 1), and belongs to the s-block. Just before it comes helium (2), and just after it comes beryllium (4). In the same column, hydrogen is above it and sodium is below it. Elements in one column tend to behave alike.
Family: Alkali metals.
Physical properties
At room temperature lithium is a solid. It melts at 180.5 °C and boils at 1,342 °C, so it stays liquid over a range of 1,161 degrees. Its density is 0.53 grams per cubic centimetre, so a one-litre block would weigh about 0.53 kilograms. It is lighter than water and would float, if it did not react with it.
Inside the atom
An atom of lithium has 3 protons in its nucleus and, when neutral, 3 electrons around it. The electrons are arranged in 2 shells: 2, 1. The outermost shell holds 1 electron. Written in full, the electron configuration is [He]2s1.
Its electronegativity on the Pauling scale is 0.98. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 5.392 electronvolts (about 520 kilojoules per mole). One mole of lithium weighs 7.0 grams, so a single gram contains about 8.60 × 1022 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains lithium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.