Question

The metal with high melting point in 4d series is

• A. $Tc$
• B. $Mo$
• C. $Cr$
• D. $W$

Answer 1

The correct option is B $Mo$

The d-block elements with more number of unpaired $e^{-}$ will have higher melting point. This is because, more the number of unpaired $e^{-}$ s present , stronger will be the metallic bond formation.
Hence, the heat required to loosen the bond will be high.
$Mo:\left[Kr\right]5s^{1}4d^5$. Has 6 unpaired electrons
$Tc:\left[Kr\right]5s^{2}4d^5$. Has 5 unpaired electrons

Since, $Mo$ contains highest number of unpaired $e^{-}$ So, it has the highest melting point out of all 4d-series elements.

$Cr$ and $W$ is of 3d and 5d series respectively.

Hence, option (b) is correct.