56Ba137.328
Alkaline Earth Metals-block
Barium
Element 56 on the periodic table, symbol Ba, group 2, period 6.
Barium is a chemical element with symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Because of its high chemical reactivity barium is never found in nature as a free element.
Properties
- Atomic Number
- 56
- Atomic Mass
- 137.3277 u
- Group
- 2
- Period
- 6
- Block
- s-block
- Category
- Alkaline Earth Metal
- State at 25 °C
- Solid
- Melting Point
- 1,000 K · 726.9 °C
- Boiling Point
- 2,118 K · 1,844.9 °C
- Density
- 3.51 g/cm³
- Atomic Radius
- 215 pm
- Electronegativity
- 0.89
- Oxidation States
- +2
- Abundance in Crust
- 425 mg/kg
- Discovered
- 1808
- Discovered By
- Carl Wilhelm Scheele
Electron Configuration
[Xe] 6s2
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2
Ionisation Energies (kJ/mol)
- 1. 502.9
- 2. 965.2
- 3. 3,600
Elements near Barium
Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.