By definition, orbitals are degenerate when they have the same energy. The 4 quantum numbers: In atoms, there are a total of 4 quantum numbers: the principal quantum number n , the angular momentum quantum number l , the magnetic quantum number ml , and the electron spin quantum number ms. When the time comes to place two electrons into the 2 p subshell we put one electron into each of two of these orbitals. In a ground state configuration, all of the electrons are in as low an energy level as it is possible for them to be. There is an obvious pattern within the vertical columns, or groups, of the periodic table as well. When one takes the spin—orbit interaction into consideration, the L and S operators no longer commute with the Hamiltonian , and their eigenvalues therefore change over time. McGraw-Hill International. A pseudovector M is represented. In mechanics, a quantum is a discrete natural unit or bundle of energy, charge, angular momentum, or other physical property. High School Chemistry Skills Practice.