Why does Hg2 + have a negative standard entropy

(-32.2J. K-1mol-1) and Hg

22+have a positive standard entropy

(84.5J. K-1mol-1) ?

Hg∧2 + has a negative standard entropy because the ions are highly solvated in aqueous phase; smaller the ionic size, the more highly it is surrounded by solvated ions. Therefore it will be in highly ordered state hence the entropy decreases.

Hg2 ^2 + has a positive standard entropy because the ionic size of Hg^2 + is smaller than Hg2 ^2+, so therefore the Hg^2 + is highly solvated and that means that it is in highly ordered state. Hg2 ^2 + is not highly solvated so it will have a positive entropy

Explanation:

The values of standard entropy of aqueous ions has a negative standard entropy because the ions are highly solvated in aqueous phase; smaller the ionic size, the more highly it is surrounded by solvated ions. Therefore it will be in highly ordered state hence the entropy decreases.

Hg2 ^2 + has a positive standard entropy because the ionic size of Hg^2 + is smaller than Hg2 ^2+, so therefore the Hg^2 + is highly solvated and that means that it is in highly ordered state. Hg2 ^2 + is not highly solvated so it will have a positive entropy