Question

The highest value of the calculated spin only magnetic moment among all the transition metal complexes:
A.$5.92$
B.$3.87$
C.$6.93$
D.$4.90$

Answer 1

To answer this question, you should recall the concept of coordination complexes and the method to calculate spin angular momentum.

Formula used: $\mu = \sqrt {n\left( {n + 2} \right)} \;{\text{BM}}$ where $n =$ Number of unpaired electrons

Complete Step by step solution:
Coordination compounds are molecules that possess one or multiple metal centres that is bound to ligands. These complexes can be neutral or charged. When the complex is charged, it is stabilized by neighbouring counter-ions. A complex ion has a metal ion at its centre with a number of other molecules or ions surrounding it. These can be considered to be attached to the central ion by coordinate bonds and in some cases, the bonding is actually more complicated than that. The molecules or ions surrounding the central metal ion are called ligands.
The spin only magnetic moment can be calculated using the formula:
$\mu = \sqrt {n\left( {n + 2} \right)} \;BM$
where $n =$ Maximum number of unpaired electrons in $M{n^{2 + }}$ = 5.
After solving this value, we have $\mu = 5.92BM$.

Hence, the correct answer for this question is option A.

Note: The coordination compounds formed by the transition elements are coloured due to the presence of unpaired electrons that absorb light in their electronic transitions. For example, the complexes containing iron (II) can exhibit green and pale green colours, but the coordination compounds containing iron (III) have a brown or yellowish-brown colour.
When the coordination centre is a metal, the corresponding coordination complexes have a magnetic nature due to the presence of unpaired electrons. Coordination compounds exhibit a variety of chemical reactivity. They can be a part of inner-sphere electron transfer reactions as well as outer-sphere electron transfers. Complex compounds with certain ligands have the ability to aid in the transformation of molecules in a catalytic or a stoichiometric manner.