It is also possible to deduce the electron configuration and bond order for ionic species.
When counting the electrons available on an ionic species, electrons must be subtracted if the species is positive and added if it is negative.
Thus the predicted electron configuration for He
2+ (3 electrons) has two electrons in the 1
sσ molecular orbital and one electron in the 1
sσ* molecular orbital. The bond order for He
2+ is therefore 0.5.
Species (like He
2+) that have unpaired electrons in molecular orbitals are paramagnetic.
Paramagnetic species tend to move toward a magnetic field.
Diamagnetic species tend to move away from an magnetic field.