kemisk tegn for aktinium - actinium.
Atomic number 89
Atomic mass 227 g.mol -1
Electronegativity according to Pauling 1.1
Density 10.07 g.cm3 at 20°C
Melting point 1050 °C
Boiling point 3250 °C
Vanderwaals radius unknown
Ionic radius unknown
Isotopes 4
Electronic shell [ Rn ] 6d1 7s2
Energy of first ionization 664.6 kJ.mol -1
Energy of second ionization 1165.5 kJ.mol -1
Discovered by André Debierne in 1899
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