Question

Classify the following atoms as diamagnetic or paramagnetic. H, O, Zn, Fe, F, Ar, He (Hint: Write down their electronic configurations) Is it true that all substances with even number of electrons are diamagnetic?

Answer 1

An atom with one or more unpaired electrons is paramagnetic; an atom with all electrons paired is diamagnetic.

Atom	Electronic configuration	Classification
H	\[[1s^{1}]\]	Paramagnetic
O	\[[1s^{2},2s^{2},2p^{4}]\]	Paramagnetic
Zn	\[\ce{[Ar] 3d^{10} 4s^{2}}]\]	Diamagnetic
Fe	\[\ce{[Ar] 3d^{6} 4s^{2}}]\]	Paramagnetic
F	\[[1s^{2},2s^{2},2p^{5}]\]	Paramagnetic
Ar	\[\ce{[Ne] 3s^{2} 3p^{6}}]\]	Diamagnetic
He	\[[1s^{2}]\]	Diamagnetic

No. An even total number of electrons does not guarantee that they are all paired. For example, oxygen has an even number of electrons but has unpaired electrons, so it is paramagnetic.