Word: elements
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Dates: during 1940-1949
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...element is a substance each of whose atoms contains the same number of electrons. Until recently, scientists thought there were 92 elements, ranging from hydrogen (with one electron circling round its nucleus) to uranium (with 92). All the intervening numbers had been accounted for. So the chemists sat back, feeling that their long search for elements had been completed...
They sat up again with a start in 1940, when University of California scientists produced a new, "synthetic" element (neptunium) by bombarding uranium with neutrons from a cyclotron. Neptunium has 93 electrons, which meant that the list of known elements was growing at the heavy end. It grew some more that same year when Dr. Glenn T. Seaborg and co-workers synthesized plutonium, which has 94 electrons...
Eventually the chemists learned so much about plutonium that they decided to use their new techniques in looking for it in nature. In pitchblende, that mineral Pandora's box of exploding elements, they found unmistakable traces: one part in 100,000,000,000,000. This was the first time that the discovery of a man-made element had led to its identification in a natural...
Conscious of the far reaching effects that any draft legislation will have on the American College scene, they asked the postponement of a final decision on universal military training, arguing that it is only one element in the comprehensive program of national defense
Conscious of the far reaching effects that any draft legislation will have on the American College scene, they asked the postponement of a final decision on universal military training, arguing that it is only one element in the comprehensive program of national defense