99Es[252]
Einsteinium
ActinidesHeavy, radioactive metals. Most of them are made only in laboratories.
[Rn] 5f¹¹ 7s²
- Atomic number
- 99
- Atomic mass
- [252]
- Protons
- 99
- Neutrons
- 153
- Electrons
- 99
- Shells
- 2, 8, 18, 32, 29, 8, 2
- State at 25 °C
- Solid
- Position
- Period 7, f-block
Proton (+)Neutron (0)Electron (−)
Discovered byAlbert Ghiorso's team, 1952Albert Ghiorso: 12 elementsGlenn T. Seaborg: 10 elementsStanley G. Thompson: 5 elements
Found in the debris of the first hydrogen bomb test, and named after Albert Einstein.
Did you know?
- Its discovery was kept secret for three years.
- Only tiny amounts have ever been made.
Where it's found
- Made only in laboratories, a few atoms at a time
What it's used for
- Scientific research only
Try it
There's no safe home experiment for Einsteinium. Explore it with the animated atom above instead.