neptunium (nĕpt
`nēəm), radioactive chemical element; symbol Np; at. no. 93; at. wt. 237.0482; m.p. about 640°C;; b.p. 3,902°C; (estimated); sp. gr. 20.25 at 20°C;; valence +3, +4, +5, or +6. Neptunium is a ductile, silvery radioactive metal. It is a member of the actinide series actinide series, a series of radioactive metallic elements in Group 3 of the periodic table . Members of the series are often called actinides, although actinium (at. no. 89) is not always considered a member of the series.
..... Click the link for more information. in Group 3 of the periodic table periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley . In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the
..... Click the link for more information. . Neptunium has three distinct forms (see allotropy allotropy (əlŏ`trəpē) [Gr.,=other form].
..... Click the link for more information. ); the orthorhombic crystalline structure occurs at room temperature. Neptunium forms numerous chemical compounds. The element was discovered in 1940 by Edwin M. McMillan McMillan, Edwin Mattison, 1907–91, American physicist, b. Redondo Beach, Calif., grad. California Institute of Technology, 1928, Ph.D. Princeton, 1932. On the faculty of the Univ.
..... Click the link for more information. and Philip H. Abelson, who produced neptunium-239 (half-life half-life, measure of the average lifetime of a radioactive substance (see radioactivity ) or an unstable subatomic particle. One half-life is the time required for one half of any given quantity of the substance to decay.
..... Click the link for more information. 2.3 days) by bombarding uranium with neutrons from a cyclotron at the Univ. of California at Berkeley. Neptunium, the first transuranium element transuranium elements, in chemistry, radioactive elements with atomic numbers greater than that of uranium (at. no. 92). All the transuranium elements of the actinide series were discovered as synthetic radioactive isotopes at the Univ.
..... Click the link for more information. , was named for the planet Neptune, which is beyond Uranus in the solar system. Neptunium is found in very small quantities in nature in association with uranium ores. There are 20 known isotopes of neptunium. Neptunium-237, the most stable, has a half-life of 2.14 million years and is used in neutron-detection equipment.
neptunium
neptunium [nep′tü·nē·əm]
`nēəm), radioactive chemical element; symbol Np; at. no. 93; at. wt. 237.0482; m.p. about 640°C;; b.p. 3,902°C; (estimated); sp. gr. 20.25 at 20°C;; valence +3, +4, +5, or +6. Neptunium is a ductile, silvery radioactive metal. It is a member of the actinide series actinide series, a series of radioactive metallic elements in Group 3 of the periodic table . Members of the series are often called actinides, although actinium (at. no. 89) is not always considered a member of the series...... Click the link for more information. in Group 3 of the periodic table periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley . In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the
..... Click the link for more information. . Neptunium has three distinct forms (see allotropy allotropy (əlŏ`trəpē) [Gr.,=other form].
..... Click the link for more information. ); the orthorhombic crystalline structure occurs at room temperature. Neptunium forms numerous chemical compounds. The element was discovered in 1940 by Edwin M. McMillan McMillan, Edwin Mattison, 1907–91, American physicist, b. Redondo Beach, Calif., grad. California Institute of Technology, 1928, Ph.D. Princeton, 1932. On the faculty of the Univ.
..... Click the link for more information. and Philip H. Abelson, who produced neptunium-239 (half-life half-life, measure of the average lifetime of a radioactive substance (see radioactivity ) or an unstable subatomic particle. One half-life is the time required for one half of any given quantity of the substance to decay.
..... Click the link for more information. 2.3 days) by bombarding uranium with neutrons from a cyclotron at the Univ. of California at Berkeley. Neptunium, the first transuranium element transuranium elements, in chemistry, radioactive elements with atomic numbers greater than that of uranium (at. no. 92). All the transuranium elements of the actinide series were discovered as synthetic radioactive isotopes at the Univ.
..... Click the link for more information. , was named for the planet Neptune, which is beyond Uranus in the solar system. Neptunium is found in very small quantities in nature in association with uranium ores. There are 20 known isotopes of neptunium. Neptunium-237, the most stable, has a half-life of 2.14 million years and is used in neutron-detection equipment.
neptunium
a silvery metallic transuranic element synthesized in the production of plutonium and occurring in trace amounts in uranium ores. Symbol: Np; atomic no.: 93; half-life of most stable isotope, 237Np: 2.14 × 106 years; valency: 3, 4, 5, or 6; relative density: 20.25; melting pt.: 639?1?C; boiling pt.: 3902?C (est.)
neptunium [nep′tü·nē·əm]
(chemistry)
A chemical element, symbol Np, atomic number 93, atomic weight 237.0482; a member of the actinide series of elements.
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|