99
Es
Einsteinium
Actinide period 7 f-block discovered: 1952
As a chemical element
Properties of the atom — they do not depend on what substance it is part of.
- Atomic number
- 99
- Atomic mass
- 252.0830 a.m.u.
- Electron configuration
- [Rn]7s2 5f11
- Electronegativity
- 1.3 on the Pauling scale
- Atomic radius
- 245 pm
- Ionization energy
- 6.42 eV
- Oxidation states
- +3
As a simple substance
Properties of the substance these atoms form under ordinary conditions.
- State at 25 °C
- Solid
- Melting point
- 1133 K (859,85 °C)