Which one of the following statement is true for transition elements

Options

A. They exhibit diamagnetism
B. They exhibit inert pair effect
C. They do not form alloys
D. They show variable oxidation states

Explanation

To determine which statement is true for transition elements, let's analyze the options provided step by step:

### Step 1: Understanding Transition Elements
Transition elements are defined as the d-block elements in the periodic table, which include elements from groups 3 to 12. They are characterized by the presence of d electrons in their penultimate shell.

### Step 2: Evaluating Each Statement
1. **They should be diamagnetic**: This statement is false. Transition elements typically have unpaired electrons in their d orbitals, which makes them paramagnetic, not diamagnetic.

2. **They do not exhibit inert-pair effect**: This statement is also false. The inert-pair effect is more commonly associated with p-block elements, particularly the heavier ones, rather than transition metals.

3. **They do not form alloys**: This statement is incorrect. Transition metals are known for their ability to form alloys with one another, which is a significant characteristic of these metals.

4. **They show variable oxidation states**: This statement is true. Transition metals can exhibit multiple oxidation states due to the presence of unpaired d electrons. For example, manganese (Mn) can have oxidation states ranging from +2 to +7.

### Step 3: Conclusion
After evaluating all the statements, the correct answer is that transition elements **show variable oxidation states**.

### Final Answer
**The true statement for transition elements is: They show variable oxidation states.**

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