The symbol of an element and dots(however many valence electrons) next to it.
Example: Ca:
Valence shell electrons. For representing the atomic bonding process.
Valence electrons are represented as dots in Lewis 'dot' structures.
H:O:H
The electron configuration of krypton is: [Ar]3d104s24p6.
It demonstrates how many valence electrons(Ve-)are in the element..