Question

Which element from group IIA will have the least ionization energy?

Answer 1

Ionization energy is the energy required to remove a loosely bound electron from its outermost shell.

As the atomic size increases, the distance of the electrons from the nucleus increases and hence, the electrons are more easily removed.

In a group, atomic size increases as the number of shells increases so ionization energy decreases.

So, element T in group IIA has the least ionization energy.