Illustrated Glossary of Organic Chemistry

Electron cloud: A group of electrons circulating around a nucleus or a molecule. Usually refers to the valence electrons.

  

Lewis structure
Methane's electron cloud.
An atom of carbon-12 (12C) consists of six
   
In methane, carbon's electron cloud consists of eight
protons (P) and six neutrons (N) in the nucleus,
valence electrons(two from each C-H covalent bond). Each
plus six electrons (E) in the electron cloud.
hydrogen atom's electron cloud contains two electrons.