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99Es252.000
Einsteinium
ActinideEinsteinium 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.
Phase: SolidAppearance: silver-colored
2, 8, 18, 32, 29, 8, 2
Physical Properties
Atomic Mass252 u
Density8.84 g/cm³
Melting Point1133 K
Boiling Point1269 K
Period7
PhaseSolid
Chemical Properties
Electron Configuration1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f11
Semantic Config[Rn] 5f11 7s2
Shells2, 8, 18, 32, 29, 8, 2
Electron Affinity-28.6 kJ/mol
Electronegativity1.3
Ionization Energies
IE1: 619 kJ/mol
Discovery
Discovered byLawrence Berkeley National Laboratory