Sodium (Na)
[Ne] 3s¹. 1 unpaired electron, period 3, 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.
NaSodium, Z = 11, 22.99 u
[Ne] 3s1
In full: 1s² 2s² 2p⁶ 3s¹
- Blocks block
- Period3
- Group1
- Valence1
- Unpaired1
- MagneticPara
Last electron 3s
- n3shell
- l0s subshell
- m0orbital
- s+½spin up
Step by step
- Sodium has 11 electrons.
- Fill in (n + l) order: 1s² 2s² 2p⁶ 3s¹.
- Write the subshells in order of n: 1s² 2s² 2p⁶ 3s¹.
- Replace the neon core with [Ne]: [Ne] 3s¹.
Sodium (Na): the numbers
| Atomic number | 11 |
|---|---|
| Atomic mass | 22.99 u |
| Period | 3 |
| Group | 1 |
| Block | s block |
| Valence electrons | 1 |
| Unpaired electrons | 1 |
| Magnetic | paramagnetic |
| Last electron | 3s: n = 3, l = 0, m = 0, s = +1/2 |
Sodium (Na): quick answers
What is the electronic configuration of sodium?
Sodium has 11 electrons: 1s² 2s² 2p⁶ 3s¹, or [Ne] 3s¹ in short.
How many unpaired electrons does sodium have?
Sodium 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 sodium?
The last electron goes into 3s: n = 3, l = 0, m = 0, s = +1/2. Orbitals fill from m = −l up, spin +½ first.