An atom has completely filled electronic shells. Which statement best explains why its permanent magnetic moment is generally zero?
Options

Question

An atom has completely filled electronic shells. Which statement best explains why its permanent magnetic moment is generally zero?

G1 Physics · Accepted Answer

Electrons in completely filled shells occur in paired quantum states. The magnetic contributions associated with paired electrons cancel, including the net spin and orbital magnetic moments of the filled shell. Hence the atom has no permanent magnetic dipole moment. However, this does NOT imply zero magnetic response: an applied field can still induce diamagnetism. Therefore option B is correct.