2.3—What is meant by the terms ‘atomic (proton) number’ and ‘mass number’

Know what is meant by the terms ‘atomic (proton) number’ and ‘mass number’.

Use —what is meant by the terms ‘atomic (proton) number’ and ‘mass number’ to connect the rule to the data and decision in the question.

This matters because —what is meant by the terms ‘atomic (proton) number’ and ‘mass number’ determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —what is meant by the terms ‘atomic (proton) number’ and ‘mass number’ to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —What is meant by the terms ‘atomic (proton) number’ and ‘mass number’ is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.