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RADIUM |
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History In the late 1800's Marie Curie made one of the last significant scientific finds of the century. Marie Curie discovered an element called she called radium. Her interest was aroused by the discovery, made in 1896 by Henri Becquerel, that compounds of uranium exhibit radioactivity. Because of this she started to do experiments with uranium to understand radioactivity. The fact that an ore of uranium (pitchblende) was four times more radioactive then uranium oxide caused her to suspect that their might be an unknown element in the ore to cause this radioactivity. With her husband Pierre Curie she repeatedly fractionally crystallized barium chloride (from pitchblende). They now had a crystalline substance that was nine hundred times more radioactive then uranium. They knew that barium was not radioactive so they reasoned that there was another element that was causing the radiation, which they announced to the world in 1898 as the element radium. It was not until 1902 that Marie Curie was able to isolate 1/10 of a gram of radium chloride that did not contain barium and it wasn't until 1910 that she was able to isolate pure radium, which is 1 million times more radioactive than uranium or thorium.
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