Question

In which of the following metallic bond is strongest?

• A. Fe
• B. Sc
• C. V
• D. Cr

Answer 1

Answer: (D)

Strength of metallic bonds depends upon number of unpaired electrons. As number of unpaired electrons increases, the bond strength increases. So $Cr,Mo,W$ show stronger bonding due to maximum number of unpaired electrons.
(a) $Fe=3d^{6}4s^2=4$ unpaired electrons
(b) $Sc=3d^{1}4s^2=1$ unpaired electron
(c) $V=3d^{3}4s^2=3$ unpaired electrons
(d) $Cr=3d^{5}4s^1=6$ unpaired electrons
Hence, $Cr$ has six unpaired electrons so, it is strongest metallic.