Terbium

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

Property	Value
Atomic Number	65
Element	Terbium
Symbol	Tb
Atomic Mass	158.925 u
Number of Neutrons	94 (most common isotope, Terbium-159)
Number of Protons	65
Number of Electrons	65
Period	6
Group	Lanthanide (no fixed group number)
Phase	Solid
Radioactive	No
Natural	Yes
Metal	Yes
Nonmetal	No
Metalloid	No
Type	Lanthanide
Atomic Radius	221 pm
Electronegativity	1.20 (Pauling scale)
First Ionization Energy	5.864 eV
Density	8.23 g/cm³
Melting Point	1356 °C
Boiling Point	3230 °C
Number of Isotopes	1 stable (Terbium-159)
Discoverer	Carl Gustaf Mosander
Year	1843
Specific Heat	0.182 J/g·K
Number of Shells	6
Number of Valence Electrons	3