2.6—The basic principles of a mass spectrometer

Understand the basic principles of a mass spectrometer and be able to analyse and interpret mass spectra to: i deduce the isotopic composition of a sample of an element ii calculate the relative atomic mass of an element from relative abundances of isotopes and vice versa iii determine the relative molecular mass of a molecule, and hence identify molecules in a sample iv understand that ions in a mass spectrometer may have a 2+ charge.

Use —the basic principles of a mass spectrometer to connect the rule to the data and decision in the question.

This matters because —the basic principles of a mass spectrometer determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the basic principles of a mass spectrometer to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The basic principles of a mass spectrometer is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.