Comparison of Californium and Einsteinium

Attribute	Einsteinium ×	Californium ×
Standard state	Solid	Solid
Electron configuration	[Rn]7s²5f¹¹	[Rn]7s²5f¹⁰
Atomic mass (u)	252.083	251.07959
Electronegativity (pauling scale)	1.3	1.3
Oxidation states	+3	+3
Ionization energy (eV)	6.42	6.3
Atomic radius (van der waals) (pm)	245	245
Melting point (K)	1133	1173
Atomic number	99	98
Group name	Actinide	Actinide
Discovered (year)	1952	1950
Symbol	Es	Cf