was it used before that?
Yes, Henri Becquerel discovered radioactivity by using uranium.
Uranium
Henri Becquerel discovered radioactivity by using uranium in 1896. Becquerel made the discovery in Paris by leaving a sample of a uranium salt, KUO(SO) (potassium uranyl sulfate), on top of an unexposed photographic plate in a drawer and noting that the plate had become "fogged". He determined that a form of invisible light or rays emitted by uranium had exposed the plate.
where did the us get uranium for the atomic bomb Congo. what is this project about? It was a research and development undertaking during World War II that produced the first nuclear weapons. what is the date of this undertaking? From 1942 to 1946. where is it based? UNANSWERABLE who manages or backs this project? It was led by the United States with the support of the United Kingdom and Canada. do you know about any particular nuclear product that it might have eveloped? In parallel with the work on uranium was an effort to produce plutonium. who discovered the former nuclear item? Martin Heinrich Klaproth.
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Uranium [SEP] Discovery
In 1841, Eugène-Melchior Péligot, Professor of Analytical Chemistry at the Conservatoire National des Arts et Métiers (Central School of Arts and Manufactures) in Paris, isolated the first sample of uranium metal by heating uranium tetrachloride with potassium. Henri Becquerel discovered radioactivity by using uranium in 1896. Becquerel made the discovery in Paris by leaving a sample of a uranium salt, KUO(SO) (potassium uranyl sulfate), on top of an unexposed photographic plate in a drawer and noting that the plate had become "fogged". He determined that a form of invisible light or rays emitted by uranium had exposed the plate.