Structure of an Atom

All matter is composed of atoms. An atom is composed of 3 types of sub-atomic particles:

  1. Protons
  2. Neutrons
  3. Electrons

The protons and neutrons are present in the center of an atom, forming a small nucleus. The electrons orbit around the nucleus in shells or energy levels.


The simplified structure of a Lithium atom is shown below:




Atoms have no overall electrical charge, however the particles contain specific charge, listed below:

Protons --- Positive (+) charge

Neutron --- Neutral (0) no charge

Electron --- Negative (–) charge