Question #5aa5a

1 Answer

Ionization energy is the energy required to remove an electron from the valence shell.

Explanation:

When we go down the group, the number of shells increase due to which the distance between the nucleus and the valence shell (last shell) increases. Due, the increased distance between nucleus and valence shell the force of attraction between the nucleus and valence shell decreases. Since, the force of attraction is very weak therefore a small amount of energy will be required to eject the electrons therefore ionization energy decreases down the group.