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Edwin Mattison McMillan (September 18, 1907 – September 7, 1991) was an American physicist credited with being the first to produce a transuranium element, neptunium.For this, he shared the 1951 Nobel Prize in Chemistry with Glenn Seaborg.
Neptunium is a chemical element; it has symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. It is named after Neptune, the planet beyond Uranus in the Solar System, which uranium is named after. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons.
Plutonium is fairly stable, but undergoes alpha-decay, which explained the presence of alpha particles coming from neptunium. [22] Thus, on March 28, 1941, Seaborg, physicist Emilio Segrè and Berkeley chemist Joseph W. Kennedy were able to show that plutonium (then known only as element 94) was fissile , an important distinction that was ...
Neptunium compounds are compounds containing the element neptunium (Np). Neptunium has five ionic oxidation states ranging from +3 to +7 when forming chemical compounds, which can be simultaneously observed in solutions. It is the heaviest actinide that can lose all its valence electrons in a stable compound.
Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. [179]
France on Thursday charged the founder of an adult website used to commit sexual offences, including by a French man who recruited dozens of strangers to rape his heavily sedated wife, prosecutors ...
Neptunium-237 and some isotopes of americium might be usable, but it is not clear that this has ever been implemented. The latter substances are part of the minor actinides in spent nuclear fuel . [ 6 ]
Neptunium-239 has 146 neutrons and a half-life of 2.356 days. It is produced via β − decay of the short-lived uranium-239 , and undergoes another β − decay to plutonium-239 . This is the primary route for making plutonium, as 239 U can be made by neutron capture in uranium-238 .