Many chemistry instructors teach beginning chemistry students the fundamentals of atomic structure by having them draw atoms based on the Bohr model of the atom. The Bohr model essentially treats atoms as miniature solar systems in which the small electrons orbit a much more massive nucleus, similar to the way planets orbit the sun. The nucleus contains uncharged neutrons and positively charged protons, whereas the orbiting electrons possess negative charges. Most helium atoms contain two protons, two neutrons and two electrons.
How to Draw a Helium AtomBy Jack Brubaker