89Ac[227]
Actinium
ActinidesHeavy, radioactive metals. Most of them are made only in laboratories.
[Rn] 6d¹ 7s²
- Atomic number
- 89
- Atomic mass
- [227]
- Protons
- 89
- Neutrons
- 138
- Electrons
- 89
- Shells
- 2, 8, 18, 32, 18, 9, 2
- State at 25 °C
- Solid
- Position
- Period 7, f-block
Proton (+)Neutron (0)Electron (−)
Discovered byAndré-Louis Debierne, 1899André-Louis Debierne: 1 element
Found in uranium ore residue. The name comes from the Greek aktis, meaning ray.
Did you know?
- It glows pale blue in the dark.
- It gives the actinide series its name.
Where it's found
- Uranium ores, in tiny amounts
What it's used for
- Targeted cancer therapy
- Neutron sources
Try it
There's no safe home experiment for Actinium. Explore it with the animated atom above instead.