Complex atoms

The Bohr model of the atom strictly applies to the simplest possible atom - Hydrogen - consisting of one proton and one orbiting electron. What of more complex atoms with more protons and electrons? Although their detailed structure is quite involved due to the complicated interactions amongst the constituents, the ideas of quantum theory discussed so far, augmented by one further assumption called the Pauli Exclusion Principle, are surprisingly successful at explaining some qualitative features. We first discuss the general structure of the periodic table.