Lithium (Li)
Alkali metal · s-block · period 2 · group 1
Soft, silvery-white metal so light it floats on water (and oil).
Lithium (symbol Li) is chemical element number 3, a alkali metal in group 1, period 2 of the periodic table. Its standard atomic weight is 6.94 and its electron configuration is [He] 2s1. At room temperature it is a solid. The least dense metal and the least dense solid element at room temperature.
Properties
| Atomic number | 3 |
|---|---|
| Atomic mass | 6.94 |
| Category | Alkali metal |
| Block | s-block |
| Group · Period | 1 · 2 |
| Electron configuration | [He] 2s1 |
| Electrons per shell | 2, 1 |
| State at 25 °C | solid |
| Melting point | 453.65 K |
| Boiling point | 1603 K |
| Density | 0.534 g/cm³ |
| Electronegativity (Pauling) | 0.98 |
| Radioactive | No |
| Origin | primordial |
| Discovered | 1817 · Johan August Arfwedson |
Key facts about Lithium
- The least dense metal and the least dense solid element at room temperature.
- Reacts steadily with water — the mildest reaction of the alkali metals.
- Gives a crimson colour to a flame.
- Stored under oil because it tarnishes in moist air.
What Lithium is used for
Rechargeable lithium-ion batteries, mood-stabilising medicine, heat-resistant glass and ceramics, lubricating greases.
Where it sits in the periodic table
Lithium is in group 1, period 2, of the s-block. Its electron configuration [He] 2s1 means its outermost shell holds 1 electron, which is what places it here and explains much of its chemistry. See Lithium on the interactive table →
Lithium — frequently asked questions
What is Lithium used for?
Rechargeable lithium-ion batteries, mood-stabilising medicine, heat-resistant glass and ceramics, lubricating greases.
Is Lithium radioactive?
No. Lithium has at least one stable isotope and is not radioactive.
What is the electron configuration of Lithium?
Lithium has the electron configuration [He] 2s1, which is 2, 1 electrons per shell.
What group and period is Lithium in?
Lithium is in group 1, period 2, in the s-block. Its outer shell holds 1 electron.
Who discovered Lithium?
Lithium was discovered in 1817 by Johan August Arfwedson.