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: Electron Configuration of Mn
The electron configuration of Mn (atomic number 25) is [Ar] 3d⁵ 4s².
Step 2: Oxidation State and Electron Loss
In the \(2+\) oxidation state, Mn loses two electrons. Thus, the electron configuration becomes [Ar] 3d⁵.
Since H₂O is a weak field ligand, it doesn't cause pairing of electrons in the \(3d\) orbitals.
Step 3: Number of Unpaired Electrons
The 3d⁵ configuration has five unpaired electrons.
Step 4: Conclusion
The number of unpaired electrons in the complex is five.
\[ \boxed{\text{The number of unpaired electrons is 5.}} \]