Neptunium

Neptunium (symbol Np) is a chemical element, atomic number 93 on the periodic table.

Characteristics and history
Neptunium, in its most stable form, has an atomic mass of 237. Neptunium was discovered by Humans on Earth's North American continent for the first time by scientists working in the United States in the year 1940. This element is part of the actinide series of heavy elements.