Lithium (Li)
Lithium is element 3, a alkali metal in period 2, group 1 of the periodic table. At room temperature it is a solid.
Electron configuration [He] 2s1
Electrons per shell 2, 1
Lithium data
| Atomic number | 3 |
|---|---|
| Symbol | Li |
| Atomic mass | 6.941 u |
| Category | Alkali metal |
| Group | 1 |
| Period | 2 |
| Block | s |
| State at 25 °C | solid |
| Melting point | 454 K (180.9 °C) |
| Boiling point | 1615 K (1341.9 °C) |
| Density | 0.535 g/cm³ |
| Electronegativity (Pauling) | 0.98 |
| Atomic radius | 134 pm |
| 1st ionization energy | 520 kJ/mol |
| Electron affinity | -60 kJ/mol |
| Oxidation states | +1 |
| Common ion charge | + |
| Discovered | 1817 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through lithium’s configuration and its ions →
Where lithium sits
Lithium belongs to the alkali metals. Its Pauling electronegativity of 0.98 is among the lowest on the table, so it gives up electrons readily; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Lithium FAQ
What is the electron configuration of lithium?
Lithium (Z = 3) has the configuration 1s2 2s1. In noble-gas shorthand that is [He] 2s1.
How many valence electrons does lithium have?
1 (outer shell (n = 2)).
What is the atomic mass of lithium?
The standard atomic weight of lithium is 6.941 u, so one mole weighs 6.941 g.
Is lithium a metal?
Yes. Lithium is a alkali metal.
What is the charge of a lithium ion?
Lithium most commonly forms Li+.