Actinium (Ac) — Element 89: Properties & Data | Aladdin Scientific
Actinium(Ac) — Element 89
Actinium (Ac) is a actinide with atomic number 89 and atomic mass 227.028. It has melting point 1324 K (1051 °C), boiling point 3471 K (3198 °C), density 10.07 g/cm³. It sits in period 7 of the periodic table and was discovered in 1899.
Key facts
| Atomic mass | 227.0277 u |
|---|---|
| Electron configuration | [Rn]7s2 6d1 |
| Oxidation states | +3 |
| Electronegativity (Pauling) | 1.1 |
| Atomic radius (van der Waals) | 260 pm |
| Ionization energy | 5.17 eV |
| Melting point | 1324 K |
| Boiling point | 3471 K |
| Density | 10.07 g/cm³ |
| Standard state | Solid |
| Year discovered | 1899 |
Frequently asked questions
What is the electron configuration of actinium?
The ground-state electron configuration of actinium is [Rn]7s2 6d1.
What group and period is actinium in?
Actinium (Ac) is in period 7 (actinide series) of the periodic table, classified as a actinide.
What is the melting point of actinium?
Actinium melts at 1324 K (1051 °C).
What is the standard state of actinium?
Actinium is a solid at standard temperature and pressure.
Related elements
About this data: property values compiled from IUPAC Standard Atomic Weights (2021), the NIST Atomic Spectra Database, and PubChem. Curated by the Aladdin Scientific technical team. Last reviewed: .