Question

Amongst the following ions which one has the highest magnetic moment Value?

• A. $\left[Cr\right(H_{2}O{)}_6{]}^{3+}$
• B. $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
• C. $\left[Zn\right(H_{2}O{)}_6{]}^{2+}$
• D. none of these

Answer 1

The correct option is B $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$

Solution: As we know, the magnetic moment is given by,

$\mu \sqrt{n(n+2)}$

where, n is the number of unpaired electrons.

For, ${\left[Cr\right(H_{2}O{)}_6]}^{3+}$ the number of unpaired electrons are 3.

So, the magnetic moment is 3.87 BM. (1)

For, ${\left[Fe\right(H_{2}O{)}_6]}^{2+}$ the number of unpair electrons are 4.

So, the magnetic moment is 4.89 BM. (2)

For, ${\left[Zn\right(H_{2}O{)}_6]}^{2+}$ the number of unpair electron is 0.

So, the magnetic moment is zero. (3)

From (1), (2) and (3)

(2) has the highest magnetic moment.

Hence, the correct option is (B).