a silver-colored, radioactive, metallic chemical element, one of the actinides, produced by bombarding uranium atoms with neutrons: symbol, Np; at. no. 93
Origin of neptuniumModern Latin ; from Classical Latin Neptunus (see Neptune) + -ium: so named by E. M. McMillan and amp; P. Abelson (1913-2004), United States physicists, because its atomic number is next after that of uranium, as the planet Neptune is next beyond Uranus
A silvery, metallic, naturally radioactive element, atomic number 93, the first of the transuranium elements. Its longest-lived isotope is Np-237 with a half-life of 2.1 million years. Found in trace quantities in uranium ores, it is produced synthetically by nuclear reactions. See Periodic Table.
Origin of neptuniumAfter the planet Neptune (from the fact that it follows uranium in the periodic table).
- The transuranic chemical element with atomic number 93 and symbol Np.
After Neptune (the planet).