The Structure of the Atom (AQA GCSE Chemistry)

Revision Note

Stewart Hird

Last updated

Relative electrical charges of subatomic particles

  • Protons, neutrons and electrons are the subatomic particles that make up atoms

Relative electrical charges

Atomic Structure Mass and Charge Distribution

The mass of the atom is concentrated in the positively charged nucleus which is attracted to the negatively charged

  • Each of the subatomic particles has a different electric charge, which is summarised in the following table

Sub-Atomic Particle Comparison (Charge) Table

Particle

Charge

Proton

+1

Neutron

0 (neutral)

Electron

-1

  • Atoms are neutral overall

    • Even though they contain charged subatomic particles, the charges cancel each other out in an atom

  • Since the charge on a proton is +1 and on an electron is -1, then the number of protons must be the same as the number of electrons for the charges to cancel each other out and produce a neutral atom

Examiner Tips and Tricks

Protons are Positive sub-atomic particles while Neutrons are Neutral. That leaves the electrons which must therefore be negative.

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Stewart Hird

Author: Stewart Hird

Expertise: Chemistry Lead

Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.