Larger the number of unpaired electrons, the more paramagnetism it has. The correct option is [Fe(H2O)6]2+
Paramagnetic character ∝ Number of unpaired electrons. So, in this paramagnetic character is maximum in [Fe(H2O)6]2+
- [Cr(H2O)6]3+:3d3: 3 unpaired electrons
- [Fe(H2O)6]2+:3d6: 4 unpaired electrons. Has maximum magnetic moment.
- [Zn(H2O)6]2+:3d10:0 unpaired electrons and is diamagnetic.
Paramagnetism refers to a property of certain materials that are weakly attracted to magnetic fields. When exposed to an external magnetic field, internal induced magnetic fields form in these materials that are ordered in the same direction as the applied field.