How do you determine whether a molecule is diamagnetic or paramagnetic?

To determine if a molecule is diamagnetic or paramagnetic, examine its electron configuration and the presence of unpaired electrons. A molecule is diamagnetic if all its electrons are paired, resulting in no net magnetic moment. Conversely, if there are unpaired electrons, the molecule is paramagnetic and will be attracted to a magnetic field. This can often be assessed using molecular orbital theory or through visualizing the electron distribution in the molecule.