In general the melting and boiling points of transition metals

Options

A. Increase gradually across the period from left to right.
B. Decrease gradually across the period from left to right.
C. First increase till the middle of the period and then increase towards the end.
D. First decrease regularly till the middle of the period and then increase towards the end.

Answer

C

Explanation

Along the period , the number of unpaired electrons increases and then decreases due to the pairing to electrons so inter-atomic forces (i.e., metallic bond) increases upto middle of the series and then decreases .Boiling and melting points are directly proportionate to strength of metallic bond.