Comparison of Berkelium and Californium

Attribute	Berkelium ×	Californium ×
Atomic mass (u)	247.07031	251.07959
Standard state	Solid	Solid
Oxidation states	+3 +4	+3
Electron configuration	[Rn]7s²5f⁹	[Rn]7s²5f¹⁰
Atomic radius (van der waals) (pm)	244	245
Electronegativity (pauling scale)	1.3	1.3
Melting point (K)	1323	1173
^1↑Ionization energy (eV)	6.23	6.3
Density (g/cm³)	14	-
Atomic number	97	98
Group name	Actinide	Actinide
Symbol	Bk	Cf
Discovered (year)	1949	1950