Which is most paramagnetic among `Cu^(2+), Fe^(2+) and Cr^(3+) ` and why?

Explanation

From the electronic configuration it is observed that the number of unpaired electrons in `Cu^(2+), Fe^(2+) and Cr^(3+)` ions are 1,4 and 3 respectively. So `Fe^(2+)` ion, containing higher number of unpaired electrons, will be most paramagnetic.