Barium (Ba) - Element 56 | Properties & Electron Configuration
What is Barium?
Barium (Ba) is element 56, a alkaline earth metal in period 6, group 2. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 6s².
| Atomic Number | 56 |
| Symbol | Ba |
| Atomic Mass | 137.33 u |
| Category | Alkaline Earth Metal |
| Period | 6 |
| Group | 2 |
| Block | s |
| Electron Configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 6s² |
| Short Config | [Xe] 6s² |
| Electronegativity | 0.89 |
| Atomic Radius | 215 pm |
| Ionization Energy | 503 kJ/mol |
| Electron Affinity | 14 kJ/mol |
| Phase (STP) | Solid |
Electron Configuration
The full electron configuration of Barium is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 6s². In noble gas shorthand, this is written as [Xe] 6s².
Barium is a s-block element in group 2, period 6.
Periodic Trends
Electronegativity: Barium has a Pauling electronegativity of 0.89. Within group 2, electronegativity generally decreases down the group.
Atomic Radius: 215 pm. Across period 6, atomic radius generally decreases left to right as nuclear charge increases.
Ionization Energy: 503 kJ/mol. Ionization energy generally increases across a period and decreases down a group.
View all 118 elements with trend overlays for electronegativity, atomic radius, ionization energy, and electron affinity.
Explore Barium on the Interactive Periodic TableRelated Topics
Beryllium (Be)
Properties of Beryllium - same group as Barium
Magnesium (Mg)
Properties of Magnesium - same group as Barium
Calcium (Ca)
Properties of Calcium - same group as Barium
Cesium (Cs)
Properties of Cesium - same period as Barium
Lanthanum (La)
Properties of Lanthanum - same period as Barium
Cerium (Ce)
Properties of Cerium - same period as Barium