Manganese () and Technetium () exhibit comparatively lower melting points than the adjacent elements — d and f Block Elements Chemistry Question

💡 Solution & Explanation

$Mn$ ($3d^5 4s^2$) and $Tc$ ($4d^5 5s^2$ according to typical stable representations) possess exactly half-filled, highly stable $d$ -orbitals. Because these $d$ -electrons are tightly held and stabilized by exchange energy, they participate less effectively in delocalized metallic bonding. This significantly weakens the metallic lattice, causing a distinct dip in their melting points compared to adjacent metals like $Cr$ or $Fe$.