Lithium (Li) – element 3
Lithium is a chemical element with the symbol Li and atomic number 3. It is a alkali metal in group 1 (alkali metals), period 2 of the periodic table (s-block), and is a solid at room temperature.
Lithium (Li) has atomic number 3, atomic mass 6.94 u and electron configuration [He] 2s1.
Lithium facts
| Symbol | Li |
|---|---|
| Atomic number | 3 |
| Atomic mass | 6.94 u (g/mol) |
| Category | alkali metal |
| Group | group 1 (alkali metals) |
| Period | 2 |
| Block | s-block |
| Phase at 20 °C | Solid |
| Electron configuration | 1s2 2s1 |
| Noble-gas notation | [He] 2s1 |
| Electrons per shell | 2, 1 |
| Valence electrons | 1 |
Bohr model and shells
Lithium has 3 electrons in 2 shells: 2, 1. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 453.65 K (180.5 °C) |
|---|---|
| Boiling point | 1603 K (1329.8 °C) |
| Density | 0.534 g/cm³ |
| Electronegativity (Pauling) | 0.98 |
| Electron affinity | 59.6326 kJ/mol |
| Ionization energies | 520.2, 7298.1, 11815 kJ/mol (1st, 2nd, 3rd) |
| Molar heat capacity | 24.86 J/(mol·K) |
| Discovered by | Johan August Arfwedson |
Use the atomic mass in the molar mass calculator for any formula containing Li.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of lithium?
The atomic mass of lithium is 6.94 u, so one mole of lithium atoms weighs 6.94 g.
What is the electron configuration of lithium?
Lithium has 3 electrons: 1s² 2s¹, or [He] 2s¹ in noble-gas notation. Electrons per shell: 2, 1.
How many valence electrons does lithium have?
Lithium has 1 valence electron (group 1).
Is lithium a metal?
Yes. Lithium is a alkali metal.
Where is lithium on the periodic table?
Lithium is in group 1 (alkali metals), period 2, in the s-block.
Data: Periodic-Table-JSON (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.