Comparison of Yttrium and Terbium

Attribute	Yttrium ×	Terbium ×
Atomic mass (u)	88.90584	158.92535
Standard state	Solid	Solid
Oxidation states	+3	+3
Electron configuration	[Kr]5s²4d¹	[Xe]6s²4f⁹
Atomic radius (van der waals) (pm)	219	221
Electronegativity (pauling scale)	1.22	-
Electron affinity (eV)	0.307	-
Ionization energy (eV)	6.217	5.864
Boiling point (K)	3618	3503
Melting point (K)	1795	1629
Density (g/cm³)	4.47	8.23
Atomic number	39	65
Group name	Transition metal	Lanthanide
Symbol	Y	Tb
Discovered (year)	1794	1843