Octquadnilium (Oqn)
Octquadnilium is the systematic name of the theoretical 840. element in the periodic table with a symbol of Oqn and atomic number of 840. Octquadnilium, also known as element 840, has οκτακόσια σαράντα protons in its nucleus, and οκτακόσια σαράντα electrons in its shells.