37 - Rubidium alkali metal
Discovered by Robert Bunsen in 1861
Rubidium is a chemical element with symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group, with an atomic mass of 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other alkali metals, such as very rapid oxidation in air.
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 | 8 | 2 in 4s + 6 in 4p |
| 5 | 1 | 1 in 5s |
Electron shells
grey white Appearance
85.5 u Atomic Mass
2.35 Å Atomic Radius
961 K Boiling Point
1 Group
1 Common Oxidation States
2.2 Å Covalent Radius
1.53 g/cm³ Density
46.9 kJ/mol Electron Affinity
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 Electron Configuration
[Kr] 5s1 Electron Configuration (semantic)
0.82 Electronegativity
37 Electrons
4.18 eV First Ionization Energy
1 ICSD Oxidation States
403, 2633, 3860, 5080, 6850, 8140, 9570, 13120, 14500, 26740 kJ/mol Ionization Energies
313 K Melting Point
9 Mendeleev Number
31.1 J/(mol·K) Molar Heat
5 Number of Shells
1 Electron Valency
48 Neutrons
37 Atomic Number
20 Number of Isotopes
1 Oxidation States
5 Period
Solid Phase
37 Protons
2, 8, 18, 8, 1 Electron Shell Occupations
0.363 J/(g K) Specific Heat