37Rb85.468
Alkali Metals-block
Rubidium
Element 37 on the periodic table, symbol Rb, group 1, period 5.
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.
Appearance: grey white
Properties
- Atomic Number
- 37
- Atomic Mass
- 85.4678 u
- Group
- 1
- Period
- 5
- Block
- s-block
- Category
- Alkali Metal
- State at 25 °C
- Solid
- Melting Point
- 312.5 K · 39.3 °C
- Boiling Point
- 961 K · 687.9 °C
- Density
- 1.532 g/cm³
- Atomic Radius
- 235 pm
- Electronegativity
- 0.82
- Oxidation States
- +1
- Abundance in Crust
- 90 mg/kg
- Discovered
- 1861
- Discovered By
- Robert Bunsen
Electron Configuration
[Kr] 5s1
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1
Ionisation Energies (kJ/mol)
- 1. 403
- 2. 2,633
- 3. 3,860
- 4. 5,080
- 5. 6,850
- 6. 8,140
- 7. 9,570
- 8. 13,120
Elements near Rubidium
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.