Barium (Ba)
[Xe] 6s². 0 unpaired electrons, period 6, group 2, 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.
BaBarium, Z = 56, 137.327 u
[Xe] 6s2
In full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 6s²
- Blocks block
- Period6
- Group2
- Valence2
- Unpaired0
- MagneticDia
Last electron 6s
- n6shell
- l0s subshell
- m0orbital
- s−½spin down
Step by step
- Barium has 56 electrons.
- Fill in (n + l) order: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s².
- Write the subshells in order of n: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 6s².
- Replace the xenon core with [Xe]: [Xe] 6s².
Barium (Ba): the numbers
| Atomic number | 56 |
|---|---|
| Atomic mass | 137.327 u |
| Period | 6 |
| Group | 2 |
| Block | s block |
| Valence electrons | 2 |
| Unpaired electrons | 0 |
| Magnetic | diamagnetic |
| Last electron | 6s: n = 6, l = 0, m = 0, s = −1/2 |
Barium (Ba): quick answers
What is the electronic configuration of barium?
Barium has 56 electrons: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 6s², or [Xe] 6s² in short.
How many unpaired electrons does barium have?
Barium has 0 unpaired electrons, so it is diamagnetic. 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 barium?
The last electron goes into 6s: n = 6, l = 0, m = 0, s = −1/2. Orbitals fill from m = −l up, spin +½ first.