Quick Facts
| Property | Value |
|---|---|
| Symbol | Ac |
| Atomic Number | 89 |
| Atomic Mass | [227] u |
| Category | Actinide |
| Period | 7 |
| Group | 3 |
| Block | f |
| Electron Configuration | [Rn] 6d¹ 7s² |
History and Discovery
Discovered by: André-Louis Debierne Year of Discovery: 1899 Location: Paris, France
Etymology
From Greek "aktis" meaning "ray," due to its radioactivity.
Applications and Uses
- Actinium-225 for cancer treatment (targeted alpha therapy)
- Neutron source (with beryllium)
- Research on actinide chemistry
Interesting Facts
- Gives its name to the actinide series
- Glows in the dark due to intense radioactivity
- About 150 times more radioactive than radium
- Ac-225 shows promise for treating leukemia
- Very rare—estimated 0.002 ppm in Earth's crust