Question

In first transition series, the melting point of $Mn$ is low because

• A. due to $d^{10}$ configuration, metallic bonds are strong
• B. due to $d^7$ configuration, metallic bonds are weak
• C. due to $d^5$ configuration, metallic bonds are weak
• D. None of these

Answer 1

Answer: (C)

Due to $d^5$ configuration, $Mn$ has exactly half filled $d$-orbitals. As a result, the electronic configuration is stable which means $3d$ electrons are more tightly held by the nucleus and this reduces the delocalization of electrons resulting in weaker metallic bonding.