Search this website:

This web page location:

home page  >   Chemical Elements  >   Radium

Chemical Elements


alpha rays, Pierre Curie, zinc sulfide, clock dials, alkaline earth metals

Deeper web pages:

>  Properties and Occurence

Radium (Latin radius, ”ray”), symbol Ra, chemically reactive, silvery white, radioactive metallic element. In group 2 (or IIa) of the periodic table, radium is one of the alkaline earth metals. The atomic number of radium is 88.

Radium was discovered in the ore pitchblende by the French chemists Marie Curie and Pierre Curie in 1898. They discovered that the ore was more radioactive than its principal component, uranium, could account for. They separated the ore into many chemical fractions in order to isolate the unknown sources of radioactivity. One fraction, isolated by use of bismuth sulfide, contained a strongly radioactive substance that the Curies showed was a new element, polonium. A highly radioactive barium-chloride fraction was treated to remove another radioactive substance, which was discovered to be a second new element, radium.


Radiation from radium has a harmful effect upon living cells, and radium burns are caused by overexposure to the rays. Cancerous cells, however, are often more sensitive to radiation than normal cells, and such cells may be killed without seriously injuring healthy tissue by controlling the intensity and direction of the radiation. Radium is now used in the treatment of only a few kinds of cancer; radium chloride or radium bromide is enclosed in a sealed tube and inserted in the diseased tissue. When a radium salt is mixed with a substance such as zinc sulfide, the substance is caused to luminesce by the bombardment of the alpha rays emitted by the radium. Small amounts of radium were once used in the production of luminous paint, which was applied to clock dials, doorknobs, and other objects, to make them glow in the dark.

Article key phrases:

alpha rays, Pierre Curie, zinc sulfide, clock dials, alkaline earth metals, polonium, Curies, doorknobs, Radium, periodic table, principal component, radioactive substance, new element, IIa, overexposure, Cancerous cells, uranium, living cells, bombardment, kinds of cancer, normal cells, glow, intensity, Radiation, substance, ray, direction, objects, treatment, dark, Uses, group, order

Search this website: