Question

Calculate the number of unpaired electrons in [Mn(H₂O)₆]²⁺, considering H₂O as a weak field ligand. (Atomic number of Mn = 25)

• A. Two
• B. Three
• C. Four
• D. Five

Hint:

In weak field ligands like H\textsubscript{2}O, the electrons in the d-orbitals do not pair up, leading to a higher number of unpaired electrons.

Answer 1

The Correct Option is D

Step 1: Mn's Electron Configuration
Mn (atomic number 25) has an electron configuration of [Ar] 3d⁵ 4s².
Step 2: Oxidation State and Electron Loss
In the \(2+\) oxidation state, Mn loses two electrons, resulting in the configuration [Ar] 3d⁵.
H₂O is a weak field ligand and does not cause electron pairing in the \(3d\) orbitals.
Step 3: Unpaired Electron Count
The 3d⁵ configuration features five unpaired electrons.
Step 4: Conclusion
The complex has five unpaired electrons.
\[ \boxed{\text{The number of unpaired electrons is 5.}} \]