The chemical element of atomic number 88, a rare radioactive metal of the alkaline earth series. It was formerly used as a source of radiation for radiotherapy.
Radium is the most reactive member of the alkaline earth metals. It is rare in nature, occurring chiefly as an impurity in uranium ores. Radium was formerly used extensively in the treatment of tumours and in luminous materials, but it has now been largely replaced by other substances for these purposes‘Rutherford was studying the structure of matter by bombarding a very thin gold foil with the alpha radiation from radium and polonium.’
- ‘All isotopes of radium are radioactive with radium - 226 being the most stable.’
- ‘The ability of radioactive substances such as radium to radiate energy, apparently spontaneously and continuously, appeared to contradict the law of the conservation of energy.’
- ‘Radon is present in the atmosphere because it is constantly being formed during the radioactive decay of uranium and radium.’
- ‘Initial autopsies showed high amounts of radium and cesium in four deer livers.’
Late 19th century from Latin radius ‘ray’ + -ium.