Periodic table of the elements
RadiumActiniumThorium
89
Ac
Actinium
(227)
2
8
18
32
18
9
2
89
Ac
Actinium
(227)
2
8
18
32
18
9
2
General
NameActinium
SymbolAc
Number89
Chemical seriesActinides
Group / Period0 / 7
Blockf-block
CAS registry number7440-34-8

Actinium is a radioactive element

Physical properties
Statesolid
Density10.07 g/cm3
Melting point1323 K (1050 °C, 1922 °F)
Boiling point3471 K (3198 °C, 5788 °F)
Critical point

Atomic properties
Atomic Weight(227) g/mol
Crystal structurecubic face centered
Electronegativity1.10
Atomic radius195 pm
Atomic radius (calculated)
Electron configuration[Rn] 6d1 7s2
Electrons per shell2, 8, 18, 32, 18, 9, 2
Number of protons89
Number of neutrons138

Other languages
SpanishActinio
PortugueseActínio
FrenchActinium
GermanActinium
ItalianAttinio
RussianАктиний
PolishAktyn
Chinese
Arabicأكتينيوم
TurkishAktinyum
DutchActinium


Periodic table of the elements
RadiumActiniumThorium