The substances which contain species with unpaired electrons in their orbitals behave as paramagnetic sustances. Such substances are weakly attracted by the magnetic field. The paramagnetism is expressed in terms of magnetic moment. The magnetic moment is related to the number of unpaired electrons according tot he following relation:
Magnetic moment `mu=sqrt(n(n+2))BM`
where n=number of unpaired electrons.
BM stands for Bohr magneton, a unit of magnetic moment.
`1BM=(eh)/(4pimc)=9.27xx10^(-24)Am^(2)` or `JT^(-1)`
Q. Which of the following ions are diamagnetic?

Options

A. `He^(2+)`
B. `Sc^(3+)`
C. `Mg^(2+)`
D. `O^(2-)`

Answer

B, C, D