Question

Which of the following outermost electronic configuration of the element shows the highest oxidation state?

• A. \(3d^3 4s^2\)
• B. \(3d^5 4s^1\)
• C. \(3d^5 4s^2\)
• D. \(3d^6 4s^2\)
• E. \(3d^2 4s^2\)

Hint:

Maximum oxidation state in transition metals is often equal to total valence electrons, especially for elements with half-filled \(d^5\) configuration like Mn.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The maximum possible oxidation state for a transition metal is generally achieved when it loses all of its valence electrons, which includes the electrons in both the outer 's' subshell and the inner 'd' subshell. We need to find the configuration that has the maximum total number of such valence electrons.
Step 2: Detailed Explanation:
Let's identify the element corresponding to each configuration and determine its maximum possible oxidation state by summing the number of d-electrons and s-electrons.

(A) 3d\(^3\)4s\(^2\): This is the configuration for Vanadium (V). It has 3 + 2 = 5 valence electrons. Its highest oxidation state is +5.

(B) 3d\(^5\)4s\(^1\): This is the configuration for Chromium (Cr). It has 5 + 1 = 6 valence electrons. Its highest oxidation state is +6 (found in compounds like CrO\(_3\) and K\(_2\)Cr\(_2\)O\(_7\)).

(C) 3d\(^5\)4s\(^2\): This is the configuration for Manganese (Mn). It has 5 + 2 = 7 valence electrons. Its highest oxidation state is +7 (found in compounds like KMnO\(_4\) and Mn\(_2\)O\(_7\)).

(D) 3d\(^6\)4s\(^2\): This is the configuration for Iron (Fe). It has 6 + 2 = 8 valence electrons. However, due to increasing nuclear charge and pairing of d-electrons, it becomes harder to remove all of them. The highest common oxidation state for iron is +3, though states up to +6 are known, they are rare. The maximum oxidation state is lower than the total number of valence electrons.

(E) 3d\(^2\)4s\(^2\): This is the configuration for Titanium (Ti). It has 2 + 2 = 4 valence electrons. Its highest oxidation state is +4.

Step 3: Final Answer:
Comparing the maximum oxidation states: +5 (V), +6 (Cr), +7 (Mn), +6 (Fe, rare), +4 (Ti). The highest oxidation state of +7 is shown by the element with the configuration 3d\(^5\)4s\(^2\) (Manganese). This corresponds to option (C).