G8: Atomic Museum: Periodic Table

Valence electrons are the s and p electrons in the outermost shell. T

Because valence electrons are so important, atoms are often represented by simple diagrams that show only their valence electrons.

The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell.

In general, the elements that obey this rule include the s-block elements and the p-block elements (except hydrogen, helium, and lithium).

Includes exceptions