Isotopes and relative atomic mass
I can write and use the standard nuclear notation for different elements and their isotopes, and calculate relative atomic mass using isotope masses and abundancies.
Isotopes and relative atomic mass
I can write and use the standard nuclear notation for different elements and their isotopes, and calculate relative atomic mass using isotope masses and abundancies.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Atoms of many elements vary in the exact number of neutrons in their nucleus, and each version is called an isotope.
- Existence of isotopes results in relative atomic masses of some elements not being whole numbers.
- Standard nuclear notation shows the chemical symbol, the mass number and the atomic number of the isotope.
- The relative atomic mass is an average value that takes account of the abundance of the isotopes of the element.
Keywords
Isotope - An atom of an element with the same number of protons, but different mass numbers due to different numbers of neutrons.
Proton - A subatomic particle found in the nucleus with a relative mass of 1 and a positive charge (+1).
Neutron - A subatomic particle found in the nucleus with a relative mass of 1 and no charge.
Mass number - Is the total number of protons and neutrons in the nucleus of an atom.
Relative atomic mass (element) - The relative atomic mass of an element is an average value that takes account of the abundance of the isotopes of the element.
Common misconception
Students often confuse the subatomic particle responsible for making an atom an isotope, and how isotopes are responsible for the relative atomic masses to 1 d.p.
Practice determining the number of neutrons in multiple isotopes.
To help you plan your year 10 chemistry lesson on: Isotopes and relative atomic mass, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 10 chemistry lesson on: Isotopes and relative atomic mass, 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.
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Explore more key stage 4 chemistry lessons from the Atomic structure and the periodic table unit, dive into the full secondary chemistry curriculum, or learn more about lesson planning.
Licence
Lesson video
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Starter quiz
6 Questions
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10
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22
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Exit quiz
6 Questions
Subatomic particles with a mass of 1 and a positive charge.
Total number of protons and neutrons in an atom.
Atoms of an element with different numbers of neutrons.
Subatomic particles with a mass of 1 and no charge.