The metals of group 2 from top to bottom are Be, Mg, Ca, Sr, and Ba

(i) Which one of these elements will form ions most readily and why ?

(ii) State the common feature in their electronic configuration.

(i) Barium forms ions more readily due to large atomic size and low ionisation energy. Among the given elements Barium has the largest atomic size because as we move down the group atomic size increases. With increase in atomic size, the ionisation energy decreases.

(ii) The common feature in their electronic configuration are:

1. There are two electrons in their valence shell.
2. They lose two electrons to gain stable gas electronic configuration.