Assertion (A): Transition metals have high melting points.
Reason (R): Transition metals have incompletely filled d-orbitals.
Reason (R): Transition metals have incompletely filled d-orbitals.
Show Hint
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
The Correct Option is A
Solution and Explanation
The melting points of transition metals depend on the strength of the metallic bonds holding their crystal lattices together.
Step 2: Meaning
Stronger metallic bonding requires more energy to disrupt, leading directly to a higher melting point.
Step 3: Analysis
The strength of these metallic bonds is primarily determined by the number of unpaired electrons. Transition metals have incompletely filled d-orbitals, which provide these unpaired electrons. The greater the number of unpaired d-electrons available to participate in delocalization, the stronger the interatomic metallic bonding.
Step 4: Conclusion
Because the incompletely filled d-orbitals facilitate stronger metallic bonding, the assertion is true and the reason provides the correct explanation for it.
Final Answer: (A)
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