Periodic table / Neptunium

Overview

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.

Electron configuration

The electron configuration of Neptunium is [Rn] 5f4 6d1 7s2, with electron shells of 2, 8, 18, 32, 22, 9, 2.

Physical and chemical properties

Neptunium is classified as a actinide. It has an atomic mass of 237 and exists as a solid at standard conditions, appearing as silvery metallic.

Real-world uses of Neptunium

Neptunium is an actinide studied primarily in nuclear science and research due to its radioactive properties.

Interesting facts about Neptunium

• Neptunium has the atomic number 93 and chemical symbol Np.
• It belongs to period 7, group 3 of the periodic table.
• Neptunium was discovered by Edwin McMillan.

Explore Neptunium interactively

Want to compare Neptunium with other elements or see it highlighted on the full table? Open the interactive periodic table and click on Np to explore properties, trends, and neighboring elements. You can also test your knowledge with our periodic table quiz game.