89
Ac
Actinium
Actinium
Actinium (Ac)
Actinides · Solid · Period 7 · Group 3
Element Properties
- Atomic Number
- 89
- Symbol
- Ac
- Atomic Mass
- 227.0277
- Category
- Actinides
- Standard State
- Solid
- Period
- 7
- Group
- 3
- Electronegativity
- 1.1
- Atomic Radius
- 260
- Ionization Energy
- 5.17
- Electron Affinity
- —
- Oxidation States
- +3
- Melting Point
- 1324 K (1050.85 °C)
- Boiling Point
- 3471 K (3197.85 °C)
- Density
- 10.07
- Electron Configuration
- [Rn]7s2 6d1
- Year Discovered
- 1899
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Frequently asked questions
What is the atomic number of Actinium?
The atomic number of Actinium is 89, which equals the number of protons in its nucleus.
What is the atomic mass of Actinium?
The atomic mass of Actinium is approximately 227.0277 u (one twelfth of the mass of a carbon-12 atom).
What is the electron configuration of Actinium?
The electron configuration of Actinium is [Rn]7s2 6d1.
Where is Actinium in the periodic table?
Actinium is located in period 7, group 3.
When was Actinium discovered?
Actinium was discovered in 1899.
Related elements
Same group
21
Sc
Scandium
44.956
39
Y
Yttrium
88.906
57
La
Lanthanum
138.905
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.908
60
Nd
Neodymium
144.24