Same chapter3 marksDifficulty: Medium
Arrange Na+, Mg2+, F− and O2− in order of increasing ionic radius and give the reason.
Classification of Elements and Periodicity in Properties
3 marksDifficulty: Medium
Why is the second ionisation enthalpy of an element always greater than the first?
Original Khojo Papers practice question — not from a past board paper.
Answer
After the first electron has been removed the species is a positive ion, so the remaining electrons are held by the same nuclear charge but there are fewer of them and the ion is smaller. The effective nuclear pull on each is therefore greater and more energy is needed to remove the next.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The jump is very large where removal would break a noble gas configuration.
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