Einsteinium

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General Properties
Atomic number Predicted atomic mass Half-life of longest living isotope Electron Configuration First developed
99 252amu Around 470 days [Rn] 5f11 7s2 1952
General Properties
Atomic number 99
Atomic mass 252amu
Half-life of longest living isotope Around 470 days
Electron Configuration [Rn] 5f11 7s2
First discovered 1952

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Description and uses

Einsteinium is the 99th element of the periodic table. It was discovered in 1952 after a sample of nuclear fallout material was analysed, and found to contain a few hundred atoms of a new element. The isotope with the longest half-life is 252Es, with a half life of around 470 days.

T&C