![]() ![]() The unit curie is not exactly equal to the activity of one gram of radium, but it is a close approximation. Take care to take the order of magnitude correctly. Note: Knowledge of activity of 1 gram of radium in disintegrations per second or the SI unit becquerel is important to find the answer to this question. The meeting where the unit Curie was defined originally proposed for 1 curie to be the activity of 10 nanograms of radium, but Marie Curie insisted on it being 1 gram as she thought the use of the name Curie for such a small amount of anything is inappropriate. The use of this unit is discouraged but still is widely used by many people. But the unit Curie remained the same as defined earlier. ![]() So, 1 Curie will be equal to 37 billion becquerels. One disintegration per second is defined as one becquerel. Its activity is approximately equal to 37 billion disintegrations per second. Thus, the chemical individuality of radium was completely established, and the reality of radio elements was a known fact about which there could be no further controversy.Hint: We tell how 1 curie is the activity of 1 gram of radium and how much that is in disintegrations per second and if it does not match any of the options, use the other units given in the option and then pick the one which matches.ġ Curie is defined as the activity of 1 gram of radium. I made a first determination of the atomic weight of this new element, an atomic weight much higher than that of barium. In 1902 I succeeded in preparing a decigram of chloride of pure radium which gave only the spectrum of the new element, radium. In 1924, Marie Curie wrote: The radium-bearing barium was extracted in the factory, and I carried on its purification and fractional crystallization in the laboratory. The fact that no other element had the same atomic weight confirmed the discovery of radium. 2 This number is consistent with the currently accepted value of 226.0 atomic mass units. I consider this number to be accurate within one unit. In 1903, she published a dissertation in which she wrote: From these experiments, I have determined that radium’s atomic weight is Ra = 225. Marie Curie conducted a series of experiments to measure radium’s atomic weight. By 1902, after a great deal of effort, they had managed to extract 0.1 gram of radium chloride from the 13 tons of residues. The Curies received two tons of residues in 1899, six tons in 1900 and five tons in 1902. Over several years, they managed to obtain residues from uranium mines in Joachimsthal (now Jáchymov), Bohemia, free of charge. They therefore needed to get their hands on some uranium ore. To determine the atomic weight of radium, which involved a series of extremely precise weighings, the Curies first had to extract the purest radium possible from uranium ore. According to a notice in Nature at the time, it was to be named in honour of Pierre Curie, but was considered at least by some to be in honour of Marie SkodowskaCurie as well, and is in later literature considered to be named for both. This weight is what makes each element unique. The curie (symbol Ci) is a non-SI unit of radioactivity originally defined in 1910. 1 In the early 20th century, atomic weight represented an element’s relative weight compared to that of another reference element. To definitively confirm that radium was well and truly a new element, the Curies needed to measure its atomic weight.
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