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.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Starter quiz
6 Questions
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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.