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Neptunium Symbol Np Atomic Number 93 Atomic Mass 237.0482 Family Actinide Transuranium Element Pronunciation nep-TOO-nee-um Overview Neptunium lies in Row 7 of the periodic table. The periodic table is a chart that shows how chemical elements are...

Neptunium is a transuranium, radioactive element in the actinide series. It is denoted by the atomic symbol Np, it has the atomic number 93, and it has an atomic weight of 237. It is a silvery metal with a melting point of 1191.2°F (644° C)....

Neptunium is a transuranium element, one of the elements found in Row 7 of the periodic table after uranium (atomic number 92). Neptunium's atomic number is 93, its atomic mass is 237.0482, and its chemical symbol is Np. All isotopes of neptunium are...

Neptunium (pronounced /nɛpˈtjuːniəm/) is a chemical element with the symbol Np and atomic number 93. A silvery radioactive metallic element, neptunium is the first transuranic element and belongs to the actinide series. Its most stable isotope,...

Scientists first created the artificial element neptunium in 1940, around the time they made the first atoms of plutonium. But because plutonium turned out to be so much better for nuclear weapons, researchers have paid scant attention to neptunium. Now a team...

Costly efforts have been made to stem the possible spread of plutonium and highly enriched uranium--the two materials most often mentioned in fear-of-God stories about the danger that Russia's nukes will get loose, or that Saddam Hussein or some lookalike rogue will beg,...