GCSE Physics (Pearson IGCSE)

Topic Summaries

Atoms

Atomic notation

  • Atoms are represented using atomic notation, e.g. \(^{56}_{26}\text{Fe}\) where:
    • 56 is the mass number, which is equal to the total number of protons and neutrons in the nucleus.
    • 26 is the atomic number, equal to the number of protons in the nucleus.
    • Fe is the element the atom is of. This is determined by the atomic number.
  • The number of neutrons in a nucleus is given by \(\text{mass number}-\text{atomic number}\).

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