| From Wikipedia, the free encyclopediaEinsteinium is a synthetic element with symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide. Einsteinium was discovered as a component of the debris of the first hydrogen bomb explosion in 1952, and named after Albert Einstein. | |||||||||
Einsteinium in the periodic table | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | Es | ||||||||
| Atomic number | 99 | ||||||||
| Group | 0 | ||||||||
| Period | 7 | ||||||||
| Block | f | ||||||||
| Element category | Actinide | ||||||||
Physical properties | |||||||||
| Phase at STP | Solid | ||||||||
| Density | 8.84 g/cm3 | ||||||||
| Atomic weight | 252 u | ||||||||
| Melting point | 1133 K 859.85 °C 1579.73 °F | ||||||||
| Boiling point | 1269 K 995.85 °C 1824.53 °F | ||||||||
Atomic properties | |||||||||
| Electronegativity (Pauling Scale) | 1.3 | ||||||||
| Electron affinity | -28.6 kJ/mol | ||||||||
| Oxidation states | +2, +3, +4 () | ||||||||
| Ionization energies |
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Electron configuration | |||||||||
| Elektronkonfiguration (shorthand) | [Rn] 5f11 7s2 | ||||||||
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f11 6s2 6p6 7s2 | ||||||||
| Electrons per shell | 2, 8, 18, 32, 29, 8, 2 | ||||||||
History | |||||||||
| Discovered | 1952 | ||||||||
| Discovered by | Lawrence Berkeley National Laboratory | ||||||||