Question

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 the electronic configuration of all these elements.

Answer 1

Part 1: Formation of ions more easily:-

As we know the atomic radius increases down the group. As a result, the ionization enthalpy decreases down the group. Hence Ba will form ions most readily. This is because the distance between the electrons and nucleus is greater, so the nuclear pull of the nucleus is not much effective, and it is easy to remove electrons from the valence shell.

Part 2: Electronic configuration:-

1. Be has an electronic configuration of $2,2$
2. Mg has an electronic configuration of $2,8,2$
3. Ca has an electronic configuration of $2,8,8,2$
4. Sr has an electronic configuration of $2,8,18,8,2$
5. Ba has an electronic configuration of $2,8,18,18,8,2$
6. In all these elements we can see that all of them have 2 electrons in their valence shell, as they all belong in group 2.

Final answer:-

(i) Ba will form ions most easily due to low ionization energy, and a bigger atomic radius as compared to others.

(ii) All these elements have 2 valence electrons in their outermost shell.