Comparison of Einsteinium and Mendelevium

Attribute	Mendelevium ×	Einsteinium ×
Standard state	Solid	Solid
Electron configuration	[Rn]7s²5f¹³	[Rn]7s²5f¹¹
Atomic mass (u)	258.09843	252.083
Electronegativity (pauling scale)	1.3	1.3
Oxidation states	+2 +3	+3
Ionization energy (eV)	6.58	6.42
Atomic radius (van der waals) (pm)	-	245
Melting point (K)	1100	1133
Atomic number	101	99
Group name	Actinide	Actinide
Symbol	Md	Es
Discovered (year)	1955	1952