Actinium Ac
Electron 1
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Electron 1
Electron 2
Electron 3
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Electron 5
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Electron 7
Electron 8
Electron 1
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Electron 5
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Electron 14
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Electron 18
Electron 1
Electron 2
Electron 3
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Electron 5
Electron 6
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Electron 8
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Electron 10
Electron 11
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Electron 13
Electron 14
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Electron 18
Electron 19
Electron 20
Electron 21
Electron 22
Electron 23
Electron 24
Electron 25
Electron 26
Electron 27
Electron 28
Electron 29
Electron 30
Electron 31
Electron 32
Electron 1
Electron 2
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Electron 13
Electron 14
Electron 15
Electron 16
Electron 17
Electron 18
Electron 1
Electron 2
Electron 3
Electron 4
Electron 5
Electron 6
Electron 7
Electron 8
Electron 9
Electron 1
Electron 2
Actinium is a radioactive chemical element with symbol Ac (not to be confused with the abbreviation for an acetyl group) and atomic number 89, which was discovered in 1899. It was the first non-primordial radioactive element to be isolated. Polonium, radium and radon were observed before actinium, but they were not isolated until 1902.
89
Atomic Number
227 u
Atomic Mass
1323.15 K
Melting Point
3471 K
Boiling Point
10 g/cm³
Density
null Å
Atomic Radius
2.15 Å
Covalent Radius
1.1
Electronegativity
5.17 eV
First Ionization Energy
33.77
Electron Affinity
7
Number of Shells
2, 8, 18, 32, 18, 9, 2
Electron Shell Occupations
0.12 J/g
Specific Heat