Question

how is a paramagnetic character of a compound is related to the number of unpaired electrons

Answer 1

Substances exhibits para magnetic character due to the presence of unpaired electrons. Magnetic moment depends upon spin and orbital contribution of unpaired electrons, so magnetic moment increases with increase in unpaired electrons and hence paramagnetic character also increases.

Answer 2

the paramagnetic character exhibited by those compounds which have unpaired electrons.paramagnetic character is directly proportional to number of unpaired electrons. More the number of unpaired electrons more will be its paramagnetic behavior than any of the bivalent metal ion of the 3d transition series. this is due to 5 unpaired electrons as manganese is present in +2 state. it has configuration 3d5. maximum number of unpaired electrons possible in dsub-shell is 5. it means it has 5 unpaired electrons  so it exhibit maximum paramagnetic behavior in its transition series.