A Bohr Diagram is a way to draw a picture of an atom.  The protons and neutrons are drawn in the middle of the atom ( the nucleus) and the electrons fill the rings (orbits) that surround it.

The following rules are used:

•          Number of Protons (+ charge) = atomic number

•          Number of electrons (- charge) = atomic number

•          Number of neutrons (no charge) = atomic mass-atomic number        

  •  The first ring can hold a maximum of 2 electrons

  •  The second and third ring can hold a maximum of 8 electrons