The element with the most neutrons is uranium. Uranium has atomic number 92, which means it has 92 protons in its nucleus. However, the number of neutrons in uranium can vary, leading to different isotopes of uranium. The most common isotope, uranium-238 (U-238), has 146 neutrons, making it the isotope of uranium with the highest number of neutrons. Other isotopes of uranium, such as uranium-235 (U-235), have fewer neutrons.