2.10—How ionisation energies are influenced by the number of protons in the nucleus, the electron shielding and the sub-shell

Understand how ionisation energies are influenced by the number of protons in the nucleus, the electron shielding and the sub-shell from which the electron is removed.

Use —how ionisation energies are influenced by the number of protons in the nucleus, the electron shielding and the sub-shell to connect the rule to the data and decision in the question.

This matters because —how ionisation energies are influenced by the number of protons in the nucleus, the electron shielding and the sub-shell determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —how ionisation energies are influenced by the number of protons in the nucleus, the electron shielding and the sub-shell to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —How ionisation energies are influenced by the number of protons in the nucleus, the electron shielding and the sub-shell is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.