Einsteinium (Es)

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

SymbolEs
Atomic number99
Group0
Period7
Blockf
Element categoryActinide

Physical properties

Phase at STPSolid
Density8.84 g/cm3
Atomic weight252 u
Melting point1133 K
859.85 °C
1579.73 °F
Boiling point1269 K
995.85 °C
1824.53 °F

Atomära egenskaper

Electronegativity (Pauling Scale)1.3
Electron affinity-28.6 kJ/mol
Ionization energies
1619 kJ/mol

Electron configuration

Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f11 6s2 6p6 7s2
Electrons per shell2, 8, 18, 32, 29, 8, 2

History

Discovered1952
Discovered byLawrence Berkeley National Laboratory