Name Radium
Symbol Ra
Atomic Number 88
Atomic Mass 226.0 atomic mass units
Number of Protons 88
Number of Neutrons 138
Number of Electrons 88
Melting Point 700.0° C
Boiling Point 1737.0° C
Density 5.0 grams per cubic centimeter
Normal Phase Solid
Family Alkaline Earth Metals
Period 7
Cost $100,000 to $120,000 per gram



Origin of Name From the Latin word radius, meaning ray
Date and Place of Discovery Discovered in 1898 in France
Isolated in 1911 in France
Discovered by Discovered by: Marie Sklodowska Curie and Pierre Curie
Isolated by:  Marie Sklodowska Curie and André-Louis Debierne
Common Compounds
Interesting facts
  • It is the heaviest of the alkaline earth metals.
  • It is extremely radioactive.
  • It resembles barium in chemical behavior.
  • It is found in pitchblende, a uranium ore.
  • It reacts violently to water and oil and forms radium hydroxide, which is more unpredictable than barium.
  • Recently discovered radioisotopes are much more powerful and safer to handle.
Common Uses Previous uses, most of which are no longer in practice, were harmful to the environment and human health:
  • Luminous paints for watches, clocks and instrument dials
  • Nuclear panels
  • Aircraft switches
  • Radium chloride is used to produce radon gas used in cancer treatment
  • Current research to see if it can benefit cancer patients
  • Spas, much like the radon spas in Japan and Europe


Photo Courtesy of
Chemical Elements
Jefferson Lab
Web Elements

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