radium

1. n. an intensely radioactive metallic element that occurs in minute amounts in uranium ores Source: wordnet
2. An intensely radioactive metallic element found (combined) in minute quantities in pitchblende, and various other uranium minerals. Symbol, Ra; atomic weight, 226.4. Radium was discovered by M. and Mme. Curie, of Paris, who in 1902 separated compounds of it by a tedious process from pitchblende. Its compounds color flames carmine and give a characteristic spectrum. It resembles barium chemically. Radium preparations are remarkable for maintaining themselves at a higher temperature than their surroundings, and for their radiations, which are of three kinds: alpha rays, beta rays, and gamma rays (see these terms). By reason of these rays they ionize gases, affect photographic plates, cause sores on the skin, and produce many other striking effects. Their degree of activity depends on the proportion of radium present, but not on its state of chemical combination or on external conditions.The radioactivity of radium is therefore an atomic property, and is explained as result from a disintegration of the atom. This breaking up occurs in at least seven stages; the successive main products have been studied and are called radium emanation or exradio, radium A, radium B, radium C, etc. (The emanation is a heavy gas, the later products are solids.) These products are regarded as unstable elements, each with an atomic weight a little lower than its predecessor. It is possible that lead is the stable end product. At the same time the light gas helium is formed; it probably consists of the expelled alpha particles. The heat effect mentioned above is ascribed to the impacts of these particles. Radium, in turn, is believed to be formed indirectly by an immeasurably slow disintegration of uranium. Source: webster
3. An intensely radioactive metallic element found (combined) inminute quantities in pitchblende, and various other uranium minerals.Symbol, Ra; atomic weight, 226.4. Radium was discovered by M. andMme. Curie, of Paris, who in 1902 separated compounds of it by atedious process from pitchblende. Its compounds color flames carmineand give a characteristic spectrum. It resembles barium chemically.Radium preparations are remarkable for maintaining themselves at ahigher temperature than their surroundings, and for their radiations,which are of three kinds: alpha rays, beta rays, and gamma rays (seethese terms). By reason of these rays they ionize gases, affectphotographic plates, cause sores on the skin, and produce many otherstriking effects. Their degree of activity depends on the proportionof radium present, but not on its state of chemical combination or onexternal conditions.The radioactivity of radium is therefore anatomic property, and is explained as result from a disintegration ofthe atom. This breaking up occurs in at least seven stages; thesuccessive main products have been studied and are called radiumemanation or exradio, radium A, radium B, radium C, etc. (Theemanation is a heavy gas, the later products are solids.) Theseproducts are regarded as unstable elements, each with an atomicweight a little lower than its predecessor. It is possible that leadis the stable end product. At the same time the light gas helium isformed; it probably consists of the expelled alpha particles. Theheat effect mentioned above is ascribed to the impacts of theseparticles. Radium, in turn, is believed to be formed indirectly by animmeasurably slow disintegration of uranium. Source: adambom
4. n:100 n. an intensely radioactive metallic element that occurs in minute amounts in uranium ores Source: ecdict

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