Bohr Model

In 1913, Neils Bohr proposed his model of the atom. This pictured the atom as having a dense nucleus which was positively charged and electrons in specific circular orbits around the nucleus. The closer to the nucleus, the less energy an electron needed in on of these orbits, but it had to gain energy to go from one orbit to another that was further away from the nucleus.

Because of its simplicity and general ability to explain chemical change the Bohr model still has some usefulness today.