Question

Lithium has larger atomic size in aqueous state why?

Answer 1

For a gaseous alkali metal ion( isolated), size goes on increasing from Li (+)to Cs (+),down the group .

but situation is different for hydrated metal ions, it is exactly oopposite , because large (Charge/ size ) ratio, Li being the smallest in size ,can attract elctrostatically, large number of surrounding dipolar water molecules, thus observed trend for hydrated cations, size decreases from Li +(aq)to Cs+ (aq).

KEEP CALM
AND
SUPPORT
MATES