Question

Which 3d - series transition element has the highest melting point?

• A. Fe
• B. Cr
• C. Mn
• D. Ni

Answer 1

The correct option is B Cr

The d-block elements with more number of unpaired $e^{-}$ will have high melting point as more number of unpaired $e^{-}s$ present, stronger will be the metallic bond formation. Hence requirement of heat to loosen the bond will be high.

${}_{26}Fe:4s^{2}3d^6$

${}_{24}Cr:4s^{1}3d^5$

${}_{25}Mn:4s^{2}3d^5$

${}_{25}Ni:4s^{2}3d^8$

So, $Cr$ contains more number of unpaired $e^{-}s$ hence has high melting point.