Question

Be, Mg, Ca, Sr, Ba are group 2metals. Which of these will form ions most readily?
(A) Be
(B) Mg
(C) Sr
(D) Ba

Answer 1

Hint: In the above question, Group 2 elements are given. We have to find the metal which can form ions more readily. In other words, we have to find the element which is least attracted by the nucleus. Down the group, the ability to lose electrons increases.

Complete step by step solution
In the above question, we asked to find out the atom which can easily form ions, for that let us first arrange the molecules in increasing order of their atomic number.
The atomic number of-
-Be = 4
-Mg = 12
-Ca = 20
-Sr = 38
-Ba = 56
So, $ {\text{Be < Mg < Ca < Sr < Ba}} $
As the atomic number of the element increases, the number of the shell also increases.
The atoms of these elements have only two valence elements and the magnitude of force of attraction with the nucleus is quite small. Therefore, these elements have sufficient large atomic sizes as well as atomic radii. The atomic radii of these elements tends to increase down the Group and hence, the force of attraction between the nucleus and the outermost shell also decreases because of the screening effect or shielding effect of the nearby shells.
Therefore, Ba and the nucleus has least force of attraction and hence, it can form ions readily.
So, the correct option is option-D.

Note
-Ionic radius increases as we move from top to bottom in a periodic table.
-Ionic radius decreases as we move from left to right across a periodic table.