Lithium (Li)
[He] 2s¹. 1 unpaired electron, period 2, group 1, s block.
Element or ion
Type a symbol, a name or an atomic number, add a charge such as Fe3+ or Cl-, or tap an element in the table. Orbitals fill from m = −l up, spin +½ first.
LiLithium, Z = 3, 6.94 u
[He] 2s1
In full: 1s² 2s¹
- Blocks block
- Period2
- Group1
- Valence1
- Unpaired1
- MagneticPara
Last electron 2s
- n2shell
- l0s subshell
- m0orbital
- s+½spin up
Step by step
- Lithium has 3 electrons.
- Fill in (n + l) order: 1s² 2s¹.
- Write the subshells in order of n: 1s² 2s¹.
- Replace the helium core with [He]: [He] 2s¹.
Lithium (Li): the numbers
| Atomic number | 3 |
|---|---|
| Atomic mass | 6.94 u |
| Period | 2 |
| Group | 1 |
| Block | s block |
| Valence electrons | 1 |
| Unpaired electrons | 1 |
| Magnetic | paramagnetic |
| Last electron | 2s: n = 2, l = 0, m = 0, s = +1/2 |
Lithium (Li): quick answers
What is the electronic configuration of lithium?
Lithium has 3 electrons: 1s² 2s¹, or [He] 2s¹ in short.
How many unpaired electrons does lithium have?
Lithium has 1 unpaired electron, so it is paramagnetic. Put one electron in each box of a subshell before pairing (Hund’s rule) to see them.
What are the quantum numbers of the last electron of lithium?
The last electron goes into 2s: n = 2, l = 0, m = 0, s = +1/2. Orbitals fill from m = −l up, spin +½ first.