Lithium (Li)
Alkali metal
Lithium is the lightest metal — soft enough to cut with a knife and so light it floats on oil. It reacts steadily with water and is the key ingredient in the rechargeable batteries that power phones, laptops and electric cars.
Position on the periodic table
Atomic properties
| Atomic number | 3 |
|---|---|
| Atomic mass | 6.94 amu |
| Electron configuration | 1s2 2s1 |
| Noble gas shorthand | [He] 2s1 |
| Electrons per shell | 2, 1 |
| Valence electrons (outer shell) | 1 |
| Common oxidation states | +1 |
| Electronegativity (Pauling) | 0.98 |
| Covalent radius (approx.) | 128 pm |
| First ionization energy | 520.2 kJ/mol |
| Electron affinity | 59.6 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 0.534 g/cm³ |
| Melting point | 180.5 °C (453.65 K) |
| Boiling point | 1329.8 °C (1603 K) |
| Appearance | silvery-white |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of lithium
Lithium's ground-state electron configuration is 1s2 2s1, usually shortened to [He] 2s1. Its electrons occupy 2 shells (2, 1), placing it in period 2 of the s-block. The 1 outer-shell electron drives its bonding behaviour. Explore it interactively in the electron configuration calculator.
Uses of lithium
- Rechargeable lithium-ion batteries
- Heat-resistant glass and ceramics
- Lightweight aluminium alloys for aircraft
- Certain psychiatric medicines (as lithium salts)
Biological role: No confirmed essential role, though lithium salts are used medically under strict supervision.
Occurrence: Found in minerals such as spodumene and in brine lakes; never free in nature.
Common compounds of lithium
Li2CO3
Lithium carbonate
LiOH
Lithium hydroxide
LiCl
Lithium chloride
History and discovery
Discovered: 1817 — Johan August Arfwedson. Name origin: From Greek lithos, meaning stone, because it was found in a mineral rather than in plant material.
Johan August Arfwedson discovered lithium in 1817 while analysing the mineral petalite in Sweden.
Safety notes
Like all alkali metals, lithium reacts with water and must be stored away from moisture.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Lithium
1. What is the chemical symbol of Lithium?
2. What is the atomic number of Lithium?
3. Which category does Lithium belong to?
4. What is the state of Lithium at room temperature?
5. Which period of the periodic table is Lithium in?
Lithium FAQs
What is the atomic number of lithium?
Lithium's atomic number is 3 — every lithium atom has 3 protons in its nucleus.
What is the symbol for lithium?
Li. From Greek lithos, meaning stone, because it was found in a mineral rather than in plant material.
Is lithium a metal, nonmetal, or metalloid?
Lithium is classified as a alkali metal.
What state is lithium at room temperature?
At about 25 °C, lithium is a solid. It melts at 180.5 °C.
How many valence electrons does lithium have?
Lithium has 1 electron in its outer shell (shell pattern: 2, 1).
What is lithium used for?
Key uses include: rechargeable lithium-ion batteries; heat-resistant glass and ceramics; lightweight aluminium alloys for aircraft.
Related elements
Keep working with this element
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