Actinium |
| Symbol | Ac |
|---|---|
| Latin name | Actinium |
| Atomic number | 89 |
| Period | 7 |
| Element category | Transition elements |
| Relative atomic mass | 227.0278 |
| Group | III.B |
| Electronegativity | 1.1 |
| Oxidation numbers | 3 |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 6d1 7s2 |
| Density [g/cm3] | 10.07 |
| State | Solid |
| Melting point [°C] | 1050 |
| Boiling point [°C] | 3200 |
| Atomic radius [pm] | 195 |
| Thermal conductivity [W m-1K-1] | 12 |
| Heat capacity [J K-1g-1] | 0.12 |
| Discovery | 1899 |
| 1.st ionization energy [eV] | 5.17 |
| 2.nd ionization energy [eV] | 10.148 |
| Stable isotopes | 0 |
| Unstable isotopes | 11 |