56 - Barium alkaline earth metal
Discovered by Carl Wilhelm Scheele in 1808
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.
Periodic table
| Shell | Electrons | Orbitals |
|---|---|---|
| 1 | 2 | 2 in 1s |
| 2 | 8 | 2 in 2s + 6 in 2p |
| 3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
| 4 | 18 | 2 in 4s + 6 in 4p + 10 in 4d |
| 5 | 8 | 2 in 5s + 6 in 5p |
| 6 | 2 | 2 in 6s |
Electron shells
137 u Atomic Mass
2.15 Å Atomic Radius
2.17k K Boiling Point
2 Group
2 Common Oxidation States
2.15 Å Covalent Radius
3.51 g/cm³ Density
14 kJ/mol Electron Affinity
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 Electron Configuration
[Xe] 6s2 Electron Configuration (semantic)
0.89 Electronegativity
56 Electrons
5.21 eV First Ionization Energy
2 ICSD Oxidation States
502.9, 965.2, 3600 kJ/mol Ionization Energies
1k K Melting Point
14 Mendeleev Number
28.1 J/(mol·K) Molar Heat
6 Number of Shells
2 Electron Valency
81 Neutrons
56 Atomic Number
25 Number of Isotopes
2 Oxidation States
6 Period
Solid Phase
56 Protons
2, 8, 18, 18, 8, 2 Electron Shell Occupations