Pentbiunium (Pbu)

Pentbiunium is the systematic name of the theoretical 521. element in the periodic table with a symbol of Pbu and atomic number of 521. Pentbiunium, also known as element 521, has fënnef­honnert­eenanzwanzeg protons in its nucleus, and fënnef­honnert­eenanzwanzeg electrons in its shells.