Question
Which of the following has been arranged in order of increasing bond strength?
A.
$$Zn_2^{2 + } < Hg_2^{2 + } < Cd_2^{2 + }$$
B.
$$Cd_2^{2 + } < Hg_2^{2 + } < Zn_2^{2 + }$$
C.
$$Zn_2^{2 + } < Cd_2^{2 + } < Hg_2^{2 + }$$
D.
$$Hg_2^{2 + } < Cd_2^{2 + } < Zn_2^{2 + }$$
Answer :
$$Zn_2^{2 + } < Cd_2^{2 + } < Hg_2^{2 + }$$
Solution :
Due to poor shielding of $$4f$$ electrons, bond strength is maximum for $$H{g^ + } - H{g^ + }.$$