Question

What is ionization enthalpy? In a group when we move from top to bottom, the values of ionization enthalpies decrease. Explain giving reasons.

Answer 1

It is the energy required to make the outermost electron of a gaseous atom that leaves the nucleus and reacts.

As the distance of the nucleus from the outmost electron increases, the ionization enthalpy decreases primarily because the attraction cannot be that strong.

As the size of the atom increases down the group, the ionization enthalpy also decreases.

Answer 2

Energy required to make the outermost shell of electron