Comparison of Nickel and Yttrium

Attribute	Yttrium ×	Nickel ×
Atomic mass (u)	88.90584	58.693
Standard state	Solid	Solid
Oxidation states	+3	+2 +3
Electron configuration	[Kr]5s²4d¹	[Ar]4s²3d⁸
Atomic radius (van der waals) (pm)	219	163
Electronegativity (pauling scale)	1.22	1.91
Electron affinity (eV)	0.307	1.156
Ionization energy (eV)	6.217	7.64
Boiling point (K)	3618	3186
Melting point (K)	1795	1728
Density (g/cm³)	4.47	8.912
Atomic number	39	28
Group name	Transition metal	Transition metal
Discovered (year)	1794	1751
Symbol	Y	Ni