Periodic table (extended)

An extended periodic table was suggested by Glenn T. Seaborg in 1969. It is a logical extension of the principles behind the standard periodic table to include possible undiscovered chemical elements. All of the discovered elements are named by the International Union of Pure and Applied Chemistry (IUPAC) systematic element name standard of creating a generic name until it has been discovered, confirmed, and an official name approved.

The blue symbol on top of each column shows the placement of each element in each block in the periodic table. It does not always indicate the number of electrons in the orbital (e.g. copper). The red number at the left of each row shows the period: the last electron shell.

Helium is placed next to hydrogen instead of on top of neon because it is part of the s2 group.