Question:medium

Which of the following arrangements does not represent the correct order of properties stated against it?
(A). V2+ < Cr2+ < Mn2+ < Fe2+: Paramagnetic behavior
(B). Zn2+ < Ni2+ < Cr2+ < Fe2+: Number of unpaired electrons
(C). Sc3+ < Ti3+ < V3+ < Cr3+ < Mn3+: Number of oxidation states
(D). Co2+ < Cr2+ < Mn2+ < Ni2+: Stability in aqueous solution
Choose the correct answer from the options given below:

Show Hint

The number of unpaired electrons dictates the paramagnetic behavior, but it should not be interpreted without taking into account the experimental conditions as well as ligand field effects.
Updated On: Jan 17, 2026
  • (A), (B) and (C) only
  • (A) and (C) only
  • (A), (B) and (D)
  • (B), (C) and (D) only
Show Solution

The Correct Option is C

Solution and Explanation

An analysis of the arrangements' properties reveals:
(A) Paramagnetic Behavior: Paramagnetism arises from unpaired electrons, and its magnitude typically correlates with the number of such electrons. For instance, Fe2+ (four unpaired electrons) should exhibit greater paramagnetism than Mn2+ but less than Cr2+. Consequently, the provided order is inaccurate.
(B) Number of Unpaired Electrons: The sequence of unpaired electrons among the listed transition metal cations lacks a consistent increasing trend. For example, Cr2+ possesses 4 unpaired electrons, while Ni2+ has 2, and Zn2+ is diamagnetic. Therefore, this order is incorrect.
(C) Number of Oxidation States: Transition metals display multiple oxidation states; fewer d electrons generally result in fewer accessible oxidation states. Sc3+ exists solely as Sc3+. The stability of the 3+ state progressively increases from Ti3+ to Mn3+. Hence, the provided order is accurate.
(D) Stability in Aqueous Solution: Aqueous stability of transition metal ions depends on various factors, including charge density, hydration energy, and crystal field stabilization energy. This stability is complex, inconsistent, lacks a general trend, and is not simply predictable. Thus, the presented order is incorrect.

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