solve this

The group 2 ions have more hydration energy than gruop 1 ions (may be 5 times).This is due to smaller size. So Ca⁺² more hydrated than Na⁺¹.

hydration energy of Na⁺ is - 435 KJ mol^-1 while that of Ca ⁺² is - 1577 KJ /mol. so calcium ions are more hydrated than sodium ions [1]

CALCULATE E/Z FOR THE TWO......AND SMALLER ONE HAS LOWER VALUE FOR E/Z ...SO IT IS MORE EASILY HYDRATED

Ca²⁺ has more charge density than Na⁺ ..that's the reason why calcium ions are more hydrated than sodium ions....

if u c thru z/e ratio then more is itzz value so less is the size........since size is less so d ion has higher charge density n its attraction force gets comparitively higher than larger size atoms so all together it aatracts more H2O molecules forming BIGGER HYDRATED SIZE.........

ya agree with govind..
both size and the charge has to be considered.