Revision Notes

4.2.3 Electrons

Charge & Electrons

  • Electrons are negatively charged particles
  • Usually the number of electrons around an atom is equal to the number of (positive) protons in the nucleus of the atom, and hence the atom is neutral

atom-proton-neutron-electron, IGCSE & GCSE Physics revision notes

The number of negative electrons in an atom balances the number of positive protons


  • If, however, and object gains extra electrons, it will gain an overall negative charge
  • If it loses some of its electrons it will be left with a positive charge
    • Negative charges are the result of gaining electrons
    • Positive charges are the result of losing electrons

Electrons & Conduction

  • A conductor is a material that allows charge to flow through it
  • An insulator is a material that does not allow the flow of charge through it

The table below lists some common conductors and insulators:

Conductors and insulators table (1), IGCSE & GCSE Physics revision notes

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Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.

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