Question

Among the following, which one has the highest paramagnetism?
a) ${\text{ }}{\left[ {Cr{{\left( {{H_2}O} \right)}_6}} \right]^{3 + }}$
b) ${\text{ }}{\left[ {Fe{{\left( {{H_2}O} \right)}_6}} \right]^{2 + }}$
c) ${\text{ }}{\left[ {Cu{{\left( {{H_2}O} \right)}_6}} \right]^{2 + }}$
d) ${\text{ }}{\left[ {Zn{{\left( {{H_2}O} \right)}_6}} \right]^{2 + }}$

Answer 1

Paramagnetic electrons are electrons that are alone in an orbital. The external magnetic field causes the electron paths to realign, resulting in paramagnetic properties. In the absence of an externally applied magnetic field, paramagnets lose their magnetization because thermal motion randomises the spin orientations—aluminum, platinum, manganese, chromium, sodium, calcium, lithium, tungsten, and so on.

Complete answer: Paramagnetic electrons are electrons that are alone in an orbital. The external magnetic field causes the electron paths to realign, resulting in paramagnetic properties. In the absence of an externally applied magnetic field, paramagnets lose their magnetization because thermal motion randomises the spin orientations—aluminum, platinum, manganese, chromium, sodium, calcium, lithium, tungsten, and so on.
Properties of Paramagnetism
Paramagnetic substances have a slight magnetic dipole moment that is parallel to the magnetising field.
Magnetic susceptibility is low, but it is positive.
Inside paramagnetic materials, magnetic field lines become denser.
The magnetic field attracts the substances very weakly.
The number of unpaired electrons is directly proportional to the paramagnetic character.
The more unpaired electrons there are, the more paramagnetism it has.
Hence,
a) ${\text{ }}{\left[ {Cr{{\left( {{H_2}O} \right)}_6}} \right]^{3 + }}$- 3d³ - 3 unpaired electrons
b) ${\text{ }}{\left[ {Fe{{\left( {{H_2}O} \right)}_6}} \right]^{2 + }}$- 3d⁶ - 4 unpaired electrons
c) ${\text{ }}{\left[ {Cu{{\left( {{H_2}O} \right)}_6}} \right]^{2 + }}$ - 3d⁹ - 3 unpaired electrons
d) ${\text{ }}{\left[ {Zn{{\left( {{H_2}O} \right)}_6}} \right]^{2 + }}$- 3d¹⁰ - 0 unpaired electrons
Hence, ${\text{ }}{\left[ {Fe{{\left( {{H_2}O} \right)}_6}} \right]^{2 + }}$
is more paramagnetic in nature.

Note:
The property of some materials being weakly attracted to magnetic fields is known as paramagnetism. Internal induced magnetic fields form in these materials when they are exposed to an external magnetic field, and they are ordered in the same direction as the applied field.