On the periodic table, radium was first isolated from pitchblende by Marie and Pierre Curie.
Radium has the symbol Ra and atomic number 88. The Curies announced its discovery in 1898 after examining radioactive residues left from uranium ore. Pitchblende, now commonly called uraninite, contains uranium but also yielded materials with far greater radioactivity than uranium alone could explain.
The Curies initially isolated radium compounds rather than a large quantity of pure metallic radium. Marie Curie and André-Louis Debierne later isolated radium metal in 1910. The element’s name comes from the Latin radius, meaning ray, referring to its radioactivity.
Radium is an alkaline-earth metal and all its isotopes are radioactive. Radium-226, part of the uranium decay series, has a half-life of about 1,600 years. Early medical and consumer uses were later abandoned after the dangers of radiation exposure became clear.