From 65438 to 0897, Madame Curie chose her own research topic-the study of radioactive substances. This research project has brought her into a new scientific world. She worked hard to open up a virgin land, and finally completed the discovery of radioactive element radium, one of the most important discoveries in the history of modern science, which laid the foundation of modern radiochemistry and made great contributions to mankind.
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At the end of 1902, Madame Curie extracted one tenth of extremely pure radium chloride and accurately determined its atomic weight. Since then, the existence of radium has been confirmed.
About five years.