Question

Give reason for the following.
Ionisation potential of the element increases across a period.

Answer 1

Ionisation potential

It is the amount of energy required to remove an electron from an isolated ion in its gaseous state.

Reason for increase in Ionisation potential:-

1. As we move from left to right across the period, the atomic size decrease. This happens due to the increasing number of electrons.
2. As a result the nuclear force of attraction between the electrons and the nucleus is more.
3. Due to this increase in nuclear charge the energy required for removing 1 electron from the outermost shell is very much.

Therefore due to the increase in nuclear charge across the period the ionisation potential increases.