37
Rb
Rubidium
85.46783
281881
#37

Rubidium

alkali metal· Solid·85.46783 u

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.

Identity

Symbol
Rb
Atomic Number
37
Atomic Mass
85.46783 u
Category
alkali metal
Block
s-block
Period
5
Group
1
Appearance
grey white
Year Discovered
1861 CE
Discovered By
Robert Bunsen
Named By
red

Electrons

Configuration
[Kr] 5s1
Full Configuration
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1
Shells
2, 8, 18, 8, 1
Electronegativity
0.82
Electron Affinity
46.884
Oxidation States
+1
Ionization Energies
403, 2633, 3860, 5080, 6850 … +5 more

Physical Properties

Rubidium
State at
Solid
Melting Point
312.45
Boiling Point
961
Density
1.532
Molar Heat
31.06 J/(mol·K)
Crystal Structure
BCC
Magnetic Ordering
Paramagnetic

Mechanical

Atomic Radius
265 pm
Covalent Radius
220 pm
Van der Waals
303 pm
Metallic Radius
248 pm
Mohs Hardness
0.3
Brinell Hardness
0.216 MPa MPa
Bulk Modulus
2.5 GPa GPa
Shear Modulus
0.91 GPa GPa
Young's Modulus
2.4 GPa GPa

Thermal & Electrical

Thermal Conductivity
58.2 W/(m K) W/(m·K)
Electrical Conductivity
8 MS/m S/m
Specific Heat
363 J/(kg K) J/(g·K)
Heat of Vaporization
75.8 kJ/mol kJ/mol
Heat of Fusion
2.19 kJ/mol kJ/mol

Abundance

Universe
10.0 ppb
Sun
10.0 ppb
Meteorite
1.9 ppm
Earth's Crust
90 ppm
Ocean
120 ppb
Human Body
4.6 ppm