Mass spectrometry
I can explain how mass spectrometry is used to identify isotopes and molecular structures, and calculate relative atomic masses.
Mass spectrometry
I can explain how mass spectrometry is used to identify isotopes and molecular structures, and calculate relative atomic masses.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Isotopes are atoms of the same element with different numbers of neutrons.
- Relative abundances of isotopes can be used to calculate the relative atomic mass (RAM) of an element.
- Mass spectrometry ionises samples to create positive ions for analysis.
- The M⁺ peak represents the molecular ion, indicating the molecular mass.
- Fragmentation in mass spectrometry helps identify molecular structure by breaking molecules into smaller ions.
Keywords
Isotope - An atom of an element with the same number of protons, but different number of neutrons.
Relative atomic mass - An average value that takes account of the abundance of the isotopes of the element.
Molecular mass - The sum of the atomic masses of all the atoms in a molecule.
Molecular ion - The ion produced when the molecule is ionised by loss of an electron from the molecule.
Spectrometer - An apparatus used for recording and measuring spectra, especially as a method of analysis.
Common misconception
All peaks in a mass spectrum represent intact (and neutral) molecules or atoms.
Clarify that in mass spectrometry, all detected peaks represent ionised species, not neutral molecules or atoms. The peaks can correspond to either the molecular ion (M⁺) or smaller ionised fragments, as well as different isotopes of an element.
To help you plan your year 11 chemistry lesson on: Mass spectrometry, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 11 chemistry lesson on: Mass spectrometry, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 chemistry lessons from the Chemical analysis unit, dive into the full secondary chemistry curriculum, or learn more about lesson planning.
Licence
Lesson video
Loading...
