Question

The maximum and minimum m.p of $1^{st}$ transition and $2^{nd}$ transition series are of _______________ respectively.

• A. $Cr$ and $Zn$
• B. $Cr$ and $Cd$
• C. $Cr$ and $Hg$
• D. $Mo$ and $Cd$

Answer 1

The correct option is B $Cr$ and $Cd$

In the first transition series, chromium has maximum number of unpaired electrons (5 unpaired electrons).
It has strongest metallic bonds and maximum melting point.
In the second transition series, cadmium has no unpaired electrons.
Hence, it has minimum melting point.