Account for the following : Transition metals have high melting points.
Account for the following : Transition metals have high melting points.
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Solution and Explanation
The melting point of a metal depends on how strongly its atoms are held together by metallic bonding. The more electrons that take part in bonding, the stronger the bond.
Step 2: Electrons in transition metals.
Transition metals have partly filled \((n-1)d\) orbitals. Besides the \(ns\) electrons, the unpaired \((n-1)d\) electrons also take part in the metallic bond.
Step 3: Result.
With so many electrons shared, the metallic bonding (interatomic attraction) is very strong. A large amount of heat is needed to break it, so the melting points are high. The melting point rises as the number of unpaired d electrons increases, reaches a maximum near the middle of the series, and then falls as the d electrons get paired. Tungsten has the highest melting point among metals.
Final Answer:
Transition metals have high melting points because the unpaired \((n-1)d\) electrons, along with the \(ns\) electrons, take part in strong metallic bonding.
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