`AgI_(2)^(-)` complex is more stable than `AgF_(2)^(-)`, why?

Which one is more stable and why?

Why H_(2) is more stable than H_(2)^(+) while He_(2)^(+) is more stable than He_(2) ?

CH_(3)COO^(-) ion is more stable than C_(2)H_(5)O^(-) ion. Assign reason.

CH_(3)COO^(-) (acetate ion) is more stable than C_(2)H_(5)O^(-) (ethoxide ion). Explain.

Why is Pt(IV) more stable than Ni(IV).

Why is a ._(2)^(4)He nucleus more stable than a ._(3)^(4)Li nucles ?

Assertion:- N_(2)^(+) is more stable than N_(2)^(-) Reason:- N_(2)^(+) has less electrons in antibonding orbital .

Which is more stable Fe^(2+) or Fe^(3+)? Why ?

Assertion: H_(2)SO_(4) is a weaker acid than HClO_(4) . Reason: SO_(4)^(2-) is more stable than ClO_(4)^(-) in solution.

Cu_((aq.))^+ has less stable nature than Cu_((aq.))^(2+) but Fe_((aq.))^(3+) is more stable than Fe_((aq.))^(2+) . Half-filled and completely filled, sub-shell are more stable.