Neptunium: Difference between revisions
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imported>Mark Widmer (Opening paragraph revised to new standard: Phase, symbol, atomic no., and std. atomic weight. Updated "solid" link from disambig page to appropriate page.) |
imported>Mark Widmer (Intro paragraph: Changed "standard atomic weight" to mass of longest-lived isotope.) |
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'''Neptunium''' is a [[Chemical elements|chemical element]], typically found as a [[Solid_(state_of_matter)|solid]] in its elemental form. It has the [[chemical symbol]] Np, [[atomic number]] (number of [[protons]]) ''Z'' = 93, and a | '''Neptunium''' is a [[Chemical elements|chemical element]], typically found as a [[Solid_(state_of_matter)|solid]] in its elemental form. It has the [[chemical symbol]] Np, [[atomic number]] (number of [[protons]]) ''Z'' = 93, and its longest-lived isotope has a mass number of 237. | ||
Neptunium is considered a member of the "Transuranic" class of elements. At a [[pressure]] of 101.325 k[[Pascal (unit)|Pa]], it has a [[boiling point]] of 3,900 °[[Celsius (unit)|C]] and a [[melting point]] of 644 °C. | Neptunium is considered a member of the "Transuranic" class of elements. At a [[pressure]] of 101.325 k[[Pascal (unit)|Pa]], it has a [[boiling point]] of 3,900 °[[Celsius (unit)|C]] and a [[melting point]] of 644 °C. | ||
Revision as of 18:37, 9 January 2021
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Neptunium is a chemical element, typically found as a solid in its elemental form. It has the chemical symbol Np, atomic number (number of protons) Z = 93, and its longest-lived isotope has a mass number of 237.
Neptunium is considered a member of the "Transuranic" class of elements. At a pressure of 101.325 kPa, it has a boiling point of 3,900 °C and a melting point of 644 °C.
History
Neptunium was the first synthetic transuranium element of the actinide series to be discovered. In 1940, Edwin McMillan and Philip H. Abelson produced the isotope 239Np at the Berkeley Radiation Laboratory of the University of California, Berkeley by bombarding uranium with cyclotron-produced, slow moving neutrons.[1]
References
- ↑ Neptunium From the website of the Los Alamos National Laboratory (LANL)