89 – Ac – Actinium

Ac-227 (half life 21.8 years) is part of the decay chain of U-235, so traces of Actinium exist in the pitchblende shown here. Amount: 0.1 g pitchblende, corresponding to 12 pg or 30 billion atoms of Ac-227.

Physical and chemical data
Atomic mass	227.0278
Density	10.07 g·cm^-3
Melting point	1050 °C
Boiling point	3300 °C
Abundance	6.00e-14 %
Electronegativy	1
Oxydation levels	3
Electron configuration	[Rn]6d 7s2