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Atomic mass, symbol and atomic number
actinium is a natural element with the elementary symbol Ac and atomic number 89. In the periodic table it belongs to the actinoids with an atomic mass of 227.027 u. The chemical element discovered by André-Louis Debierne in 1899 is radioactive and is in a solid state of aggregation at room temperature.
Characteristics: Actinium (English Actinium)
| General | |
|---|---|
| Chemical element: | actinium |
| Symbol: | Ac |
| Atomic number: | 89 |
| Group: | scandium |
| Period: | 7 |
| Block: | d-block |
| Series: | Transition metals |
| Appearance: | silver |
| explorers: | André-Louis Debierne |
| Year of discovery: | 1899 |
| Atomic properties | |
| Atomic mass: | 227,027 u |
| Atomic radius: | 195 pm |
| Covalent radius: | 215 pm |
| Van der Waals radius: | ??? |
| Electron configuration: | Rn 6d1 7s2 |
| ionization: | 499 kJ / mol |
| Physical Properties | |
| Physical state: | firmly |
| Density: | ??? |
| Crystal structure: | cubic |
| Magnetism: | unknown |
| molar volume: | 22,55 · 10-6 m3/ mol |
| Mohs hardness: | ??? |
| Melting point: | 1050 ° C |
| Boiling point: | 3300 ° C |
| Heat of fusion: | 14 kJ / mol |
| Heat of vaporization: | 400 kJ / mol |
| Thermal conductivity: | 12 W |
| Chemical properties | |
| electronegativity: | 1,1 |
Did you know that ...
- Actinium is an intermediate in the decomposition of uranium?
- the chemist André-Louis Debierne first discovered the element Actinium in uranium, a highly radioactive mineral?
- Actinium is the first element in the group of Actinoids?
