Rubidium

Symbol: Rb
Atomic number: 37
Category: alkali metals
Group: 1
Period: 5
Block: s
Atomic weight: 85.4678 g/mol
Electrons per shell: 2, 8, 18, 8, 1
CAS number: 7440-17-7
Phase: solid
Density: 1.532 kg/l (near room temperature)
Melting point: 312.46 K (39.31C, 102.76F)
Boiling point: 961 K (688C, 1270F)
Crystal structure: cubic body centered
Oxidation states: 1
Electronegativity: 0.82 (Pauling scale)
Name's origin: rubidus
Name's meaning: deepest red, as it was discovered in the mineral lepidolite through the use of a spectroscope
Facts:
- is easily ionized, so it has been considered for use in ion engines for space vehicles
- was used in the discovery of Bose-Einstein condensate, which is a state of matter