Plutonium

Koushik 26/06/2026 19:58:09 Updated 26/06/2026 19:58:09

Property	Value
Atomic Number	94
Element	Plutonium
Symbol	Pu
Atomic Mass	[244] (most stable isotope)
Number of Neutrons	150 (Plutonium-244)
Number of Protons	94
Number of Electrons	94
Period	7
Group	Actinide (no fixed group number)
Phase	Solid
Radioactive	Yes
Natural	No (trace amounts occur naturally)
Metal	Yes
Nonmetal	No
Metalloid	No
Type	Actinide
Atomic Radius	~159 pm (varies with allotrope)
Electronegativity	1.28 (estimated)
First Ionization Energy	6.026 eV (estimated)
Density	19.86 g/cm³
Melting Point	640 °C
Boiling Point	3228 °C
Number of Isotopes	No stable isotopes (Pu-239, Pu-240 most notable)
Discoverer	Glenn T. Seaborg, Edwin McMillan, Joseph W. Kennedy, Arthur Wahl
Year	1940
Specific Heat	0.130 J/g·K
Number of Shells	7
Number of Valence Electrons	6