Relative electrical charges of subatomic particles — AQA GCSE Chemistry
Test yourself on Relative electrical charges of subatomic particles with AQA GCSE practice questions.
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Relative electrical charges of subatomic particles explained
Atoms contain protons, neutrons and electrons.
Read the full explanation
Protons have a relative charge of 1⁺, electrons have a relative charge of 1⁻, and neutrons have no charge. In a neutral atom, the number of electrons equals the number of protons, so the positive and negative charges balance exactly. For example, a carbon atom has six protons and six electrons, giving six positive charges and six negative charges, so the overall charge is zero. If the numbers were unequal, the atom would become a charged ion. This balance explains why atoms are electrically neutral and why the nucleus, although positive, does not make the whole atom charged.
Your focus
- State the relative electrical charges of protons, neutrons and electrons.
- Explain why an atom has no overall electrical charge.
- Apply the proton-electron balance to a specific atom to show neutrality.
Relative electrical charges of subatomic particles exam tips
Marking Points
- State the relative charge of a proton as 1⁺, an electron as 1⁻ and a neutron as 0.
- State that in an atom the number of electrons equals the number of protons.
- Explain that equal numbers of protons and electrons balance positive and negative charges.
- Conclude that an atom has no overall electrical charge because the charges cancel.
- Apply the idea to a named atom, for example carbon with six protons and six electrons, to show the balance.
Examiner Tips
- 💡Use the relative charge values 1⁺, 1⁻ and 0 when describing subatomic particles.
- 💡To justify neutrality, state that the number of protons equals the number of electrons and the charges cancel.
- 💡If asked why an atom is neutral, avoid mentioning neutrons as the reason; neutrons have no charge and do not affect the balance.
Common Mistakes
- Writing that atoms have no charge because they contain no charged particles; correct this by stating they contain equal numbers of protons and electrons whose charges cancel.
- Giving the neutron a charge; correct this by stating the neutron is neutral with relative charge 0.
- Saying the number of neutrons equals the number of protons in every atom; correct this by stating it is the number of electrons that equals the number of protons in a neutral atom.