Septbiunium (Sbu)

Septbiunium is the systematic name of the theoretical 721e element in the periodic table with a symbol of Sbu and atomic number of 721. Septbiunium, also known as element 721, has zeven­honderd­een­en­twintig protons in its nucleus, and zeven­honderd­een­en­twintig electrons in its shells.