Radium

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

Property	Value
Atomic Number	88
Element	Radium
Symbol	Ra
Atomic Mass	[226] (most stable isotope)
Number of Neutrons	138 (Radium-226)
Number of Protons	88
Number of Electrons	88
Period	7
Group	2
Phase	Solid
Radioactive	Yes
Natural	Yes (from decay of uranium and thorium)
Metal	Yes
Nonmetal	No
Metalloid	No
Type	Alkaline Earth Metal
Atomic Radius	~283 pm (estimated)
Electronegativity	0.90 (estimated)
First Ionization Energy	5.279 eV
Density	5.5 g/cm³
Melting Point	700 °C
Boiling Point	1737 °C
Number of Isotopes	No stable isotopes (Ra-226 most notable)
Discoverer	Marie Curie, Pierre Curie
Year	1898
Specific Heat	0.094 J/g·K
Number of Shells	7
Number of Valence Electrons	2