Chemistry - PERIODIC TABLE Question with Solution | TestHub

Ionisation energy of a cation is always higher than its neutral atom because electrons are removed and effective nuclear charge per electron increases. Hence removing another electron from a cation requires more energy.

For all given species—potassium ion, oxygen cation, neon cation, phosphorus cation, beryllium cation, sodium dication, iron cation, tin dication—this rule holds.

Therefore, no cation has lower I.P. than its atom