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Thursday, June 16, 2016

Rubidium chemical element

Rubidium was discovered in 1861 by the German chemist Robert Wilhelm Bunsen and physist Gustav Robert Kirchhoff.
The chemical symbol for Rubidium is Rb and its atomic number is 37.
We find it listed in the periodic table of elements in group 1 and period 5 and block s.
Rubidium belongs to the family or chemical series of alkali metals.
This element is stable, Rubidium came from rubidus.


Rubidium chemical element



Atomic number (Z) 37
Group, block group 1 (alkali metals), s-block
Period: period 5
Element category: alkali metal
Standard atomic weight (±) (Ar): 85.4678(3)[1]
Electron configuration: [Kr] 5s1
per shell 2, 8, 18, 8, 1

Physical properties:
Phase: solid
Melting point: 312.45 K (39.30 °C, 102.74 °F)
Boiling point: 961 K (688 °C, 1270 °F)
Density near r.t.: 1.532 g/cm3
when liquid, at m.p. 1.46 g/cm3
Triple point: 312.41 K, ? kPa[2]
Critical point: 2093 K, 16 MPa (extrapolated)[2]
Heat of fusion: 2.19 kJ/mol
Heat of vaporization: 69 kJ/mol
Molar heat capacity :31.060 J/(mol•K)

Atomic properties:
Oxidation states: +1, −1 (a strongly basic oxide)
Electronegativity: Pauling scale: 0.82
Ionization energies: 1st: 403 kJ/mol
2nd: 2632.1 kJ/mol
3rd: 3859.4 kJ/mol
Atomic radius empirical: 248 pm
Covalent radius: 220±9 pm
Van der Waals radius: 303 pm

Crystal structure: body-centered cubic
Speed of sound thin rod: 1300 m/s (at 20 °C)
Thermal expansion: 90 µm/(m•K)[3] (at r.t.)
Thermal conductivity: 58.2 W/(m•K)
Electrical resistivity: 128 nΩ•m (at 20 °C)