Comparison of Californium and Fermium

Attribute	Fermium ×	Californium ×
Standard state	Solid	Solid
Electron configuration	[Rn]5f¹²7s²	[Rn]7s²5f¹⁰
Atomic mass (u)	257.09511	251.07959
Electronegativity (pauling scale)	1.3	1.3
Oxidation states	+3	+3
Ionization energy (eV)	6.5	6.3
Atomic radius (van der waals) (pm)	-	245
Melting point (K)	1800	1173
Atomic number	100	98
Group name	Actinide	Actinide
Symbol	Fm	Cf
Discovered (year)	1952	1950