The quantum number provide us with a picture ofin the atom the electronic arrangement relative to the nucleus.This arranntugement is not given in terms of exact positions, like the photograph of a street,but rather in terms of probability distributions and potential energy levels, much like the mosquito swarm. The potential energy levels are described by the main quantum number n and by the secondary quantum number l. The probability distributions given by the secondary quantumumber l and the magnetic quantum number ml.