"Heaviest Entity in the Universe: Element or Object?"
Originally Published 2 years ago — by IFLScience
The heaviest element in the universe depends on how "heaviness" is defined. By atomic mass, oganesson is the heaviest element ever synthesized, with 118 protons and 176 neutrons. However, by natural occurrence, plutonium-244 is the heaviest element with 94 protons. Uranium-238 is the heaviest naturally occurring element with 92 protons. When considering density, osmium and iridium are the densest elements due to their high atomic mass and small atomic radius.