A Level Chemistry OCR Practice Exam

What does successive ionisation energy measure?

1. The energy required to remove all electrons from an atom

2. The energy required to remove each electron in turn

3. The energy required to form ions from neutral atoms

4. The energy required to stabilize an atom's electron cloud

The correct answer is: The energy required to remove each electron in turn

Successive ionisation energy specifically refers to the energy needed to remove each electron from an atom one after the other. When an atom loses its first electron, it becomes a positive ion, and the energy measured for this process is the first ionisation energy. As more electrons are removed successively, the ionisation energy required for each subsequent electron removal can change due to factors such as increased nuclear charge or electron-electron repulsion in the ion. This concept is essential in understanding the trends in ionisation energies across the periodic table, as the energy required to remove electrons often increases with each successive electron due to the strong attraction between the remaining electrons and the nucleus. Other options do not accurately capture the specific meaning of successive ionisation energy. For example, the option referring to the energy required to remove all electrons from an atom summarizes the total energy involved but does not reflect the focus on the individual steps of removing each electron. Similarly, the choice concerning the formation of ions from neutral atoms addresses a broader process, not the focus on successive removal of electrons. Lastly, the description about stabilizing an atom's electron cloud does not relate to the energy required for ionisation but rather touches on the stability of electronic configurations.