Question

Among the following ions, which one has the highest paramagnetism?

• A. $\left[Cr\right(H_{2}O{)}_6{]}^{3+}$
• B. $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
• C. $\left[Cu\right(H_{2}O{)}_6{]}^{2+}$
• D. $\left[Zn\right(H_{2}O{)}_6{]}^{2+}$

Answer 1

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

$H_{2}O$ is a weak field ligand.
The compound with highest number of unpaired electrons has highest paramagnetism. Outer electronic configuration for these ions can be given as: