37
Rb
85.468
Rubidium
Element 37 · 85.468 u · s-block
alkali metal
A soft, silvery alkali metal that ignites spontaneously in air. Used in atomic clocks and specialty glass.
Phase (STP)
Solid
Melting Point
39.31 °C
Boiling Point
688 °C
Density
1.532 g/cm³
Electronegativity
0.82
Atomic Radius
235 pm
Ionization Energy
403 kJ/mol
Electron Affinity
47 kJ/mol
Discovered
1861 · Robert Bunsen
Electron Configuration
[Kr] 5s1
Electron Orbitals
Drag to rotate · Pinch to zoom