Rubidium

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.

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

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

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 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

Discovery	Robert Bunsen, Gustav Kirchhoff (1861)
First isolation	Robert Bunsen (1863)
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.

Original word	rubidus
Language of origin	Latin
Name source	Properties
Meaning	“Dark red”
Naming The name is derived from the Latin word 'rubidius', meaning deep red because of the two "deep red lines" in its spectra.

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