CAIE A-Level Chemistry 1.4.5 Nuclear Attraction and Ionisation Energy
Practise relating ionisation energy to electrostatic attraction between the positive nucleus and the electron removed.
- Syllabus
- 2028–2030
- Course
- Chemistry 9701
- Level
- AS
Practise relating ionisation energy to electrostatic attraction between the positive nucleus and the electron removed.
The graph below shows the variation of the first ionisation energy with proton number for some elements. The letters used are not the usual symbols for the elements.

Which statement about the elements is correct?
P and X are in the same period in the Periodic Table.
The general increase from Q to X is due to increasing atomic radius.
The small decrease from R to S is due to decreased shielding.
The small decrease from U to V is due to repulsion between paired electrons.
D