Nuclear attraction is often the deciding control factor for the association of neutral molecules to a given metal ion. Which onee of the following represents the correct order of stability of the ions? [Be(H_(2)O)_(4)]^(2+),[Mg(H_(2)O)_(4)]^(2+),[Ca(H_(2)O)_(4)]^(2+) and [Sr(H_(2)O)_(4)}^(2+)

Nuclear attraction is often the deciding control factor for the associ

1.	Nuclear attraction is often the deciding control factor for the association of neutral molecules to a given metal ion. Which onee of the following represents the correct order of stability of the ions? [Be(H_(2)O)_(4)]^(2+),[Mg(H_(2)O)_(4)]^(2+),[Ca(H_(2)O)_(4)]^(2+) and [Sr(H_(2)O)_(4)}^(2+)
Answer» `[Be(H_(2)O_(4)]^(2+) GT [Sr(H_(2)O_(4)]^(2+)gt [Mg(H_(2)O)_(4)]^(2+) gt [Ca(H_(2)O)_(4)]^(2+)` `[Ca(H_(2)O)_(4)]^(2+) gt [Mg(H_(2)O)_(4)]^(2+) gt [Be(H_(2)O)_(4)]^(2+) gt gt[S(H_(2)O)_(4)]^(2+)` `[Sr(H_(2)O)_(4)]^(2+) gt [Ca(H_(2)O)_(4)]^(2+) gt [Mg(H_(2)O)_(4)]^(2+) gt [Be(H_(2)O)_(4)]^(2+)` `[Be(H_(2)O)_(4)]^(2+) gt [Mg(H_(2)O)_(4)]^(2+) gt [Ca(H_(2)O)_(4)]^(2+) gt [Srr(H_(2)O)_(4)]^(2+)` Solution :The DEGREE of HYDRATION and the amount of hydration energy decreases as the size of the ion increases from `Be^(2+)` to `Sr^(2+)`. `{:(,Be^(2+)LT,Mg^(2+)lt,Ca^(2+)lt, Sr^(2+)),("Hydration Energy "(kJ" "mol^(-1)),-2494,-1921,-1577,-1443):}` Thus, stability of hydrated ion is `[Be(H_(2)O)_(4)}^(2+) t [Mg(H_(2)O)_(4)]^(2+) gt [Ca(H_(2)O)_(4)]^(2+)gt[Sr(H_(2)O)_(4)]^(2+)`