The dominating factor responsible for the decreasing ionisation energies of the elements on moving down the group is `:`

Options

A. atomic radius
B. type of electron to be removed
C. the valence shell electron configuration
D. all of these

Answer

1

Explanation

As size of atom increases the distance between the nucleus and valence shell electron increases. As a result of this the attraction between nucleus and valence shell electron decreases. Hence less energy is required for the removal of the valence shell electron. So down the group ionisation energies decreases.