This computational experiment presents qualitative molecular orbital (QMO) and computational quantum chemistry exercises of NO, NO+, and NO–. Initially students explore several properties of the target molecules by Lewis diagrams and the QMO theory. Then, they compare qualitative conclusions with EHT and DFT calculations and explore discrepancies from the experimental results, obtained from Internet databases. Next, they investigate how several properties change with increasing basis set and obtain reliable electronic energies by extrapolation to an infinite basis set. This experiment explores not only quantum chemistry calculations, but also the power of qualitative reasoning. Additionally, it also investigates the behavior of some properties with increasing basis set and the accurate energy calculations by the extrapolation to an infinite basis set.