Question

Which of the following is not a characteristic of transition elements ?

• A. Variable oxidation states
• B. Formation of coloured compounds
• C. Formation of interstitial compounds
• D. Natural radioactivity

Hint:

Transition metals show variable oxidation states and coloured compounds due to d-electrons, but radioactivity depends on nuclear stability.

Answer 1

The Correct Option is D

Step 1: Recall common properties of transition metals.
Transition elements typically show:
- Variable oxidation states due to incomplete d-subshell
- Formation of coloured compounds due to d-d transitions
- Formation of interstitial compounds due to small size and vacant sites
Step 2: Check the option about natural radioactivity.
Natural radioactivity is a property of unstable nuclei, not a general characteristic of transition metals.
Only a few elements are radioactive, but transition elements as a group are not defined by radioactivity.
Step 3: Conclude.
Thus natural radioactivity is not a characteristic property.
Final Answer:
\[ \boxed{\text{(D) Natural radioactivity}} \]