You need to choose an atom. Helium is the easiest which has protons, neutrons and electrons.
I presume you are looking for a Bohr/Rutherford Model ((Broken Link Removed)
Thus for helium you will need a nucleus of 2 protons and 2 neutrons around which there is a circle containing 2 electrons.
Draw a simple model of an atom to show the position of each of the comstituents of the atom.
3 answers
helium
Draw