For Relative formula mass, which formula choice answer best supports this Unit 4.3 objective: Define relative formula mass, Mr, as the sum of the relative atomic masses of atoms in the numbers shown in a formula?

The correct option is 18 - correct formula choice for relative atomic mass. The calculated answer is 18.

The correct option is 18 - correct formula choice for relative atomic mass. This uses Relative Formula Mass because the objective is about define relative formula mass, Mr, as the sum of the relative atomic masses of atoms in the numbers shown in a formula. This formula choice variant asks students to separate relative atomic mass from similar Unit 4.3 calculation steps. The reasoning belongs to Relative formula mass within Chemical measurements, conservation of mass and the quantitative interpretation of chemical equations, so it should not be confused with nearby quantitative ideas such as mass, moles, concentration, yield, atom economy, or gas volume unless those are named in the objective. Use the focus term relative atomic mass to keep the answer aligned with AQA GCSE Chemistry 8462 Unit 4.3. The other options are weaker because they either use the wrong formula, the wrong unit, a vague relationship, or the wrong quantitative context.