Melting Points Of Transition Metals

The high melting points of transition metals result from strong metallic bonding. In these metals, not only the outer ns electrons but also the unpaired (n-1)d electrons can participate in the delocalised sea of electrons that binds the metal lattice. The involvement of a larger number of bonding electrons, including the d-electrons, leads to very strong interatomic bonds and consequently high melting and boiling points, with the maximum occurring near the middle of a series where the greatest number of unpaired d-electrons is available. The option of weak van der Waals forces cannot explain high melting points. The option of ionic bonding is incorrect, since pure metals are held by metallic bonds. The option of hydrogen bonding is irrelevant to metals. The role of d-electron participation in strong metallic bonding is a standard NCERT d-block property. Examiners frequently test whether a student can connect metallic bonding with the underlying principle rather than merely recalling an isolated fact. It is worth emphasising that this is not a special case but a representative example of how melting points of transition metals operates throughout d- and f-block elements. Plausibility check: the peak in melting points around the middle of a transition series, where unpaired d-electrons are most numerous, confirms that d-electron involvement strengthens metallic bonding.