Samarium

Koushik 26/06/2026 19:58:08 Updated 26/06/2026 19:58:08

Property	Value
Atomic Number	62
Element	Samarium
Symbol	Sm
Atomic Mass	150.36 u
Number of Neutrons	88 (most common isotope, Samarium-152)
Number of Protons	62
Number of Electrons	62
Period	6
Group	Lanthanide (no fixed group number)
Phase	Solid
Radioactive	No (some isotopes are radioactive)
Natural	Yes
Metal	Yes
Nonmetal	No
Metalloid	No
Type	Lanthanide
Atomic Radius	229 pm
Electronegativity	1.17 (Pauling scale)
First Ionization Energy	5.644 eV
Density	7.52 g/cm³
Melting Point	1072 °C
Boiling Point	1900 °C
Number of Isotopes	7 naturally occurring (Sm-144, Sm-147, Sm-148, Sm-149, Sm-150, Sm-152, Sm-154)
Discoverer	Paul-Émile Lecoq de Boisbaudran
Year	1879
Specific Heat	0.197 J/g·K
Number of Shells	6
Number of Valence Electrons	3