Explanation
The sum of the magnetic moment of the electron orbit, the spin magnetic moment and the magnetic moment of the atomic nucleus that are not filled with the electron shell in the atom. According to the results of quantum mechanics, the magnetic moment of the atomic nucleus is very small and can be ignored. The magnetic moment of an atom is just the sum of the magnetic moment of those electrons whose shell is not full.
Classification
Fundamental of Material Science -> Physical and chemical basis of materials