Amongst the following ions which one has the highest paramagnetism -

Question

Question

Answer 1

The correct answer is option 2) i.e. [Fe(H2O)6]2+

CONCEPT:

Paramagnetic substances: Paramagnetic substances are those substances that get weakly magnetized with the influence of an external magnetic field.
- A paramagnetic atom has spin and orbital magnetic moments aligned in such a way that they have a permanent magnetic dipole moment.
- However, due to the thermal vibrations of the atoms, these magnetic moments get aligned in random directions such that the net magnetic moment is zero.
- Under the influence of an external magnetic field, they tend to get aligned along the direction of the field. In the process, they acquire some net magnetic moment. This is called magnetization.
The spin magnetic moment is given by the equation

\(\Rightarrow \mu=\sqrt{n(n+2)}\)

Where n is the number of unpaired electrons.

CALCULATION:

Greater the value of net magnetic moment higher will be the paramagnetic nature of the material.

	Number of unpaired electrons (n)	Spin magnetic moment, μ = \(\sqrt{n(n+2)}\)
[Cr(H2O)6]3+	3	\(\sqrt{3(3+2)} \) = 3.87
[Fe(H2O)6]2+	4	\(\sqrt{4(4+2)}\) = 4.89
[Cu(H2O)6]2+	1	\(\sqrt{1(1+2)}\) = 1.73
[Zn(H2O)6]2+	0	\(\sqrt{0(0+2)}\) = 0