Tecken | Rb |
Atomnummer | 37 |
Grupp | 1 (Alkalimetaller) |
Period | 5 |
Block | s |
Ämnesklass | Alkalimetall |
Utseende | Grey white |
Färg | Silver |
Antal protoner | 37 p+ |
Antal neutroner | 48 n0 |
Antal elektroner | 37 e- |
Fas vid STP | Fast |
Densitet | 1.532 g/cm3 |
Relativ atommassa | 85.4678 u |
Smältpunkt | 312.45 K 39.3 °C 102.74 °F |
Kokpunkt | 961 K 687.85 °C 1270.13 °F |
Ångbildningsvärme | 69.2 kJ/mol |
Elektronegativitet (Paulingskalan) | 0.82 |
Elektronaffinitet | 46.884 kJ/mol |
Oxidationstal | −1, +1 (a strongly basic oxide) |
Jonisationspotential |
|
Upptäckt | Robert Bunsen, Gustav Kirchhoff (1861) |
Första isolation | George de Hevesy |
Upptäckten av 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. |