Barium (Ba)
Alkaline earth metal · s-block · period 6 · group 2
Soft, silvery-white metal that oxidises readily.
Barium (symbol Ba) is chemical element number 56, a alkaline earth metal in group 2, period 6 of the periodic table. Its standard atomic weight is 137.33 and its electron configuration is [Xe] 6s2. At room temperature it is a solid. Its name is Greek for 'heavy'.
Properties
| Atomic number | 56 |
|---|---|
| Atomic mass | 137.33 |
| Category | Alkaline earth metal |
| Block | s-block |
| Group · Period | 2 · 6 |
| Electron configuration | [Xe] 6s2 |
| Electrons per shell | 2, 8, 18, 18, 8, 2 |
| State at 25 °C | solid |
| Melting point | 1000 K |
| Boiling point | 2170 K |
| Density | 3.51 g/cm³ |
| Electronegativity (Pauling) | 0.89 |
| Radioactive | No |
| Origin | primordial |
| Discovered | 1808 · Humphry Davy |
Key facts about Barium
- Its name is Greek for 'heavy'.
- Soluble barium compounds are poisonous, but insoluble barium sulfate is safe.
- You drink a 'barium meal' of that sulfate so your gut shows up on an X-ray.
- Gives fireworks their green colour.
What Barium is used for
Medical X-ray contrast (barium sulfate), drilling muds, green fireworks, vacuum-tube getters, glass.
Where it sits in the periodic table
Barium is in group 2, period 6, of the s-block. Its electron configuration [Xe] 6s2 means its outermost shell holds 2 electrons, which is what places it here and explains much of its chemistry. See Barium on the interactive table →
Barium — frequently asked questions
What is Barium used for?
Medical X-ray contrast (barium sulfate), drilling muds, green fireworks, vacuum-tube getters, glass.
Is Barium radioactive?
No. Barium has at least one stable isotope and is not radioactive.
What is the electron configuration of Barium?
Barium has the electron configuration [Xe] 6s2, which is 2, 8, 18, 18, 8, 2 electrons per shell.
What group and period is Barium in?
Barium is in group 2, period 6, in the s-block. Its outer shell holds 2 electrons.
Who discovered Barium?
Barium was discovered in 1808 by Humphry Davy.