How heat of hydration differ in periodic table . please explain with this question

Hydration energy depends upon size of cation and charge of cation so higher the charge of cation and lower the size of cation have higher hydration energy. So, here Al 3+ will have...

The attractions are stronger the smaller the ion. For example, hydration enthalpies fall as you go down a group in the Periodic Table. The small lithium ion has by far the highest ...