Combined Science GCSE
Isotopes
What Isotopes means in Combined Science GCSE, as defined for AQA.
Definitions of Isotopes
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Reference: AQA
Atoms of the same element with the same number of protons but different numbers of neutrons, so they have the same atomic number but different mass numbers.
Discovered later, these showed that atomic weight is an average and explained why strict atomic-weight ordering sometimes failed.
Atoms of the same element can differ in neutron number, forming these, but the proton number stays fixed.
Atoms of the same element, determined by the atomic number, that are distinguished by their mass number.
Atoms of the same element with different numbers of neutrons and therefore different mass numbers.
Atoms of the same element with the same number of protons but different numbers of neutrons.
Topics that use Isotopes
- Development of the periodic table (AQA GCSE)
- Key ideas (AQA GCSE)
- Mass number, atomic number and isotopes (AQA GCSE)
- Size and mass of atoms (AQA GCSE)
Related terms
- Atomic number
- Mass number
- Nuclide notation
- Relative atomic mass
- Action at a distance
- Activation energy
- Active site
- Adaptation
Using Isotopes in the exam
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