99
Es
252
Einsteinium
Element 99 · 252 u · f-block
actinide
First identified in debris from the first hydrogen bomb test. Named after Albert Einstein.
Phase (STP)
Solid
Melting Point
860 °C
Boiling Point
—
Density
8.84 g/cm³
Electronegativity
1.3
Atomic Radius
—
Ionization Energy
619 kJ/mol
Electron Affinity
—
Discovered
1952 · Albert Ghiorso
Electron Configuration
[Rn] 5f11 7s2
Electron Orbitals
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