Neptunium (Np), element 93 – Learn Acer periodic table

Neptunium

Actinide, atomic number 93.

Neptunium is a chemical element with symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. 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.

Facts

Symbol Np. Atomic mass 237.0 u. Group 3, period 7. Electron configuration [Rn] 5f4 6d1 7s2. Electrons per shell 2, 8, 18, 32, 22, 9, 2. State at room temperature: Solid. Melting point 638.9 °C, boiling point 4173.9 °C. Discovered by Edwin McMillan.

Element data from Wikipedia, CC BY-SA 3.0.