36.941LiLithium
Lithium (Li) — element 3alkali metal · group 1, period 2
Lithium is a chemical element with the symbol Li and atomic number 3. It is an alkali metal in group 1, period 2 of the periodic table (the s-block), with a standard atomic mass of 6.941 u. At room temperature (25 °C) lithium is a solid.
💡 Known for: The lightest metal; essential for rechargeable lithium-ion batteries and used in mood-stabilising medicine.
# Lithium properties
| Symbol | Li |
|---|---|
| Atomic number | 3 |
| Atomic mass | 6.941 u |
| Category | alkali metal |
| Group | 1 |
| Period | 2 |
| Block | s-block |
| Electron configuration | [He] 2s¹ |
| Full configuration | 1s² 2s¹ |
| Electrons per shell | 2, 1 |
| Protons / electrons | 3 / 3 |
| State at 25 °C | solid |
| Melting point | 453.69 K (180.5 °C, 357 °F) |
| Boiling point | 1615 K (1341.8 °C, 2447.3 °F) |
| Density | 0.534 g/cm³ |
| Electronegativity (Pauling) | 0.98 |
| First ionization energy | 5.392 eV |
| Atomic radius | 167 pm |
| Discovered | 1817 |
# Electron configuration of lithium
The electron configuration of lithium is [He] 2s¹, written out in full as 1s² 2s¹. Its 3 electrons fill 2 shells as 2, 1, so the outermost shell holds 1 electron. As a group 1 element, lithium has 1 valence electron.
# Related elements
HeHeliumprevious elementBeBerylliumnext elementHHydrogengroup 1NaSodiumgroup 1KPotassiumgroup 1RbRubidiumgroup 1CsCaesiumgroup 1FrFranciumgroup 1
# Lithium FAQ
What is the atomic number of lithium?
The atomic number of lithium is 3: every lithium atom has 3 protons in its nucleus. Its symbol is Li.
What is the atomic mass of lithium?
The standard atomic mass of lithium is 6.941 u.
What is the electron configuration of lithium?
Lithium's electron configuration is [He] 2s¹ (1s² 2s¹), with 2, 1 electrons per shell.
Is lithium a metal?
Yes. Lithium is an alkali metal, one of the metals.
What is the melting point of lithium?
Lithium melts at 453.69 K (180.5 °C, 357 °F) and boils at 1615 K (1341.8 °C, 2447.3 °F).
What is lithium used for / known for?
The lightest metal; essential for rechargeable lithium-ion batteries and used in mood-stabilising medicine.