Question

Among the following the incorrect statement about transition metals is

• A. Cr, Mo and W have high melting points
• B. Mn³⁺ is more stable than Mn²⁺
• C. With increase in number of unpaired electrons melting point increases
• D. They show variable oxidation states

Answer 1

The Correct Option is B

Step 1: Analyze the Given Statements:
We are asked to identify the incorrect statement about transition metals from the provided options:

Statement 1: Cr, Mo, and W have high melting points.
This statement is correct. Transition metals like Cr (Chromium), Mo (Molybdenum), and W (Tungsten) are known for their high melting points due to the strong metallic bonds formed by their delocalized electrons.

Statement 3: With an increase in the number of unpaired electrons, the melting point increases.
This statement is generally true. As the number of unpaired electrons increases, the bonding between atoms becomes stronger, leading to higher melting points. However, this trend is not always linear and may vary depending on specific elements and their electron configurations.

Statement 2: Mn³⁺ is more stable than Mn²⁺.
This statement is incorrect. Mn²⁺ is more stable than Mn³⁺ because Mn²⁺ has a stable d⁵ electron configuration (half-filled d-orbitals), whereas Mn³⁺ has an unstable electron configuration. Therefore, Mn²⁺ is more stable.

Statement 4: They show variable oxidation states.
This statement is correct. Transition metals exhibit a wide range of oxidation states due to the ability of their d-electrons to participate in bonding. This is one of the defining features of transition metals.

Step 2: Conclusion:
The incorrect statement among the provided options is Statement 3, which incorrectly suggests that Mn³⁺ is more stable than Mn²⁺.

Final Answer:
The incorrect statement is: Mn³⁺ is more stable than Mn²⁺.