Energy level four (shell N) can hold 32 electrons. The maximum number of electrons for any energy level can be calculated using the formula Electron Capacity = 2(n x n), where n is the energy level.
There are six electron shells, and these have the following letter classifications: K, L, M, N, O and P. The electron capacity for each shell is as follows: K=2, L=8, M=18, N=32, O=50 and P=72. An electron shell at one of the six energy levels does not have to be full before electrons start occupying the next level. The Periodic Table details the electron configuration for elements.