Rubidium (Rb)

Rubidium is a chemical element of the periodic table with chemical symbol Rb and atomic number 37 with an atomic weight of 85.4678 u and is classed as alkali metal and is part of group 1 (alkali metal). Rubidium is solid at room temperature.

Krypton Periodic table Strontium

Rubidium in the periodic table

Symbol	Rb
Atomic number	37
Group	1 (Alkali metal)
Period	5
Block	s
Classification	Alkali Metal

Appearance	Grey white
Color	Silver

Number of protons	37 p⁺
Number of neutrons	48 n⁰
Number of electrons	37 e^-

From Wikipedia, the free encyclopediaRubidium 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.

Physical properties

Phase at STP	Solid
Density	1.532 g/cm³
Atomic weight	85.4678 u

Thermal properties

Melting point	312.45 K 39.3 °C 102.74 °F
Boiling point	961 K 687.85 °C 1270.13 °F
Heat of vaporization	69.2 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)	0.82
Electron affinity	46.884 kJ/mol
Oxidation states	−1, +1 (a strongly basic oxide)
Ionization energies	403 kJ/mol 2633 kJ/mol 3860 kJ/mol 5080 kJ/mol 6850 kJ/mol 8140 kJ/mol 9570 kJ/mol 13120 kJ/mol 14500 kJ/mol 26740 kJ/mol

Electron configuration for rubidium

Electron configuration

Shorthand configuration

[Kr] 5s¹

Electron configuration

Full configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s¹

Electron configuration chart

1s²
2s²	2p⁶
3s²	3p⁶	3d¹⁰
4s²	4p⁶
5s¹

Electrons per shell

2, 8, 18, 8, 1

Valence electrons

1

Valency electrons

1

Bohr model

Figure: Shell diagram of Rubidium (Rb) atom.

Orbital Diagram

1s
2s	2p
3s	3p	3d
4s	4p
5s

The history of Rubidium

Discovery	Robert Bunsen, Gustav Kirchhoff (1861)
First isolation	George de Hevesy
Discovery of rubidium Rubidium was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff, in Heidelberg, Germany, in the mineral lepidolite through flame spectroscopy. Because of the bright red lines in its emission spectrum, they chose a name derived from the Latin word rubidus, meaning "deep red". The slight radioactivity of rubidium was discovered in 1908, but that was before the theory of isotopes was established in 1910, and the low level of activity (half-life greater than 1010 years) made interpretation complicated.

Periodic table history

Identifiers

List of unique identifiers for Rubidium in various chemical registry databases

CAS Number	7440-17-7
ChemSpider ID	4512975
EC number	231-126-6
PubChem CID Number	5357696