99 Es 252
Einsteinium
Actinide
Einsteinium (Es) is a chemical element with atomic number 99, classified as a actinide. At room temperature it is a solid. It was discovered in 1952 by Albert Ghiorso et al..
Properties
- Atomic number
- 99
- Atomic mass
- 252 u
- Category
- Actinide
- Group
- 0
- Period
- 7
- Block
- f-block
- Electron configuration
- [Rn] 5f¹¹ 7s²
- Phase at STP
- Solid
- Density
- 8.84 g/cm³
- Melting point
- 1133 K (859.9 °C)
- Boiling point
- 1269 K (995.9 °C)
- Electronegativity
- 1.3
- Atomic radius
- 245 pm
- Ionization energy
- 6.42 eV
- Discovery
- 1952 · Albert Ghiorso et al.
Common uses
Research only
Did you know?
Named after Albert Einstein and first found in hydrogen bomb debris.