Comparison of Berkelium and Mendelevium

Attribute	Mendelevium ×	Berkelium ×
Atomic mass (u)	258.09843	247.07031
Standard state	Solid	Solid
Oxidation states	+2 +3	+3 +4
Electron configuration	[Rn]7s²5f¹³	[Rn]7s²5f⁹
Atomic radius (van der waals) (pm)	-	244
Electronegativity (pauling scale)	1.3	1.3
Melting point (K)	1100	1323
Ionization energy (eV)	6.58	6.23
Density (g/cm³)	-	14
Atomic number	101	97
Group name	Actinide	Actinide
Symbol	Md	Bk
Discovered (year)	1955	1949