Comparison of Scandium and Erbium

Attribute	Scandium ×	Erbium ×
Atomic mass (u)	44.95591	167.26
Standard state	Solid	Solid
Oxidation states	+3	+3
Electron configuration	[Ar]4s²3d¹	[Xe]6s²4f¹²
Atomic radius (van der waals) (pm)	211	235
Electronegativity (pauling scale)	1.36	1.24
Electron affinity (eV)	0.188	-
Ionization energy (eV)	6.561	6.108
Boiling point (K)	3109	3141
Melting point (K)	1814	1802
Density (g/cm³)	2.99	9.07
Atomic number	21	68
Group name	Transition metal	Lanthanide
Symbol	Sc	Er
Discovered (year)	1879	1843