The chemical element with atomic number 93 in the periodic table is neptunium (Np). Neptunium is a synthetic element, meaning it does not occur naturally in significant quantities on Earth and is primarily produced in nuclear reactors or particle accelerators. It was first synthesized in 1940 by Edwin McMillan and Philip H. Abelson. Neptunium is a radioactive metal and is named after the planet Neptune, which is the next planet beyond Uranus in our solar system.