Spectroscopic notation is a method used to describe the electronic structure of atoms, particularly in quantum mechanics. It involves designating the principal quantum number (n) and the angular momentum quantum number (l) to indicate the energy levels and subshells of electrons. The discussion highlights confusion regarding the impact of the principal quantum number n=4 on orbital placement. The user initially struggled with their homework but later resolved their issue. Understanding spectroscopic notation is crucial for accurately determining electron configurations and solving related problems.