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Q.
In first transition series, the melting point of $Mn$ is low because
The d-and f-Block Elements
Solution:
Due to $d^5$ configuration, $Mn$ has exactly half filled $d$-orbitals. As a result, the electronic configuration is stable which means $3 d$ electrons are more tightly held by the nucleus and this reduces the delocalization of electrons resulting in weaker metallic bonding.