Neptunium is a chemical element with symbol Np and atomic number 93. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus. None of the above. A radioactive metal, neptunium is the first transuranic element, and belongs to the actinide series. In this quiz you’ll be shown all 118 chemical symbols, and you’ll need to choose the name of the chemical element that each one represents. All transuranic elements are unstable and decay into other elements radioactively. https://www.britannica.com/science/neptunium, Los Alamos National Laboratory's Chemistry Division - Neptunium, Neptunium - Student Encyclopedia (Ages 11 and up). This is because of the similarity of the electron energies of the 5f, 6d, an… Save my name, email, and website in this browser for the next time I comment. Neptunium was discovered in the year of 1940 by two men named Edwin McMillan and Phillip H. Abelson at Berkeley Radiation Center of the … 3 Uses 3.1 Uses & Benefits Currently known uses of Neptunium metal are limited to research purpose only. Successful synthesis of the first transuranium metal–organic frameworks (TRU-MOFs) involving tetravalent Np 4+ is reported. Symbol of the Neptunium element is Np. Though traces of neptunium have subsequently been found in nature, where it is not primeval but produced by neutron-induced transmutation reactions in uranium ores, American physicist Edwin M. McMillan and chemist Philip H. Abelson first found neptunium in 1940 after uranium had been bombarded by neutrons from the cyclotron at Berkeley, California. Neptunium’s isotope neptunium-237 is used as a neutron detectors. Neptunium is chemically reactive and is more similar to plutonium than to uranium, with oxidation states from +3 to +7. It is a radioactive actinide metal, neptunium is the first transuranic element. This differs from the configuration expected by the Aufbau principle in that one electron is in the 6d subshell instead of being as expected in the 5f subshell. Neptunium, a silvery metal, exists in three crystalline modifications; the room-temperature form (alpha) is orthorhombic. Some claims of a fourth allotrope have been made, but they are so far not proven. Neptunium is a silvery, ductile, radioactive metal. This reaction proceeds more rapidly as the temperature increa… It is a hard, silvery, ductile, radioactive actinide metal. neptunium synonyms, neptunium pronunciation, neptunium translation, English dictionary definition of neptunium. Uses: Neptunium-237 is used in neutron-detection equipment. chemical element with atomic number 93 which means there are 93 protons and 93 electrons in the atomic structure It found in at least three allotropes. All neptunium isotopes are radioactive; the stablest is neptunium-237, with a half-life of 2,144,000 years, and among the most unstable is neptunium-225, with a half-life of more than 2 microseconds. The phase transformations in neptunium metal were studied by thermal ; analysis, dilatometry, and resistivity measurements. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. McMillan and Abelson bombarded uranium-238 with neutrons and they were able to show chemically that they had produced neptunium-239, which has a half-life of just 2.3 days… Biological role. A silvery radioactive metallic element, neptunium is the first transuranic element and belongs to the actinide series. The crystal structures of neptunium, protactinium, uranium, and plutonium do not have clear analogs among the lanthanides and are more similar to those of the 3d transition metals. Neptunium metal is scarce and hard to obtain. The element occurs in three allotropic forms and it normally exhibits five oxidation states, ranging from +3 to +7. The real neptunium sits between uranium and plutonium in the actinides, the floating bar on the periodic table that pops out from between radium and lawrencium. Neptunium is a hard, silvery, ductile, radioactive actinide metal. It then transmutes into protactinium 233 (element 91). It is a common product of plutonium fission, and emits both α- and γ-particles. Neptunium in the oxide form and much of it is radioactive, olive green crystalline! Is orthorhombic and capable of accumulating in bones, which makes the handling neptunium. Nuclear waste as a mixture with other fission products plated silver which is itself alloyed with americium-241 to... Agreeing to news, offers, and resistivity measurements Abelson in 1940 at Berkeley Radiation Laboratory of periodic... 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