Isotopes
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
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Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
- Same chemical properties
- Different mass numbers
- Some isotopes are radioactive
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Isotopes?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Isotopes. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.
Check that you can explain Isotopes in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Isotopes explains how the physical world behaves, from sport and transport to electricity and medicine.
Isotopes in detail
Isotopes are atoms of the same element, with the same number of protons, but different numbers of neutrons, so they have different mass numbers. Carbon-12 and carbon-14 both have 6 protons, but 6 and 8 neutrons.
Isotopes have the same chemical properties, because the electron arrangement is the same, but some are unstable and radioactive. The relative atomic mass of an element is a weighted average of its isotopes. Isotopes are used in carbon dating, medical tracers and nuclear power.
How the interactive helps you understand Isotopes
Watch the atom model in the interactive. Use any sliders or buttons it offers to change the values and see how the atom model responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Isotopes.
Real-life uses and examples
- Use Isotopes to make sense of a practical and its results.
- Answer “explain” questions by linking Isotopes to a clear cause and effect.
- Predict what a ball, car or circuit will do with Isotopes before you do the calculation.
Common mistakes to avoid
- Mixing up Isotopes with a related quantity that has different units.
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Isotopes
What is Isotopes?
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
What are the most important points about Isotopes?
The main points are: Same chemical properties; Different mass numbers; Some isotopes are radioactive.
Why is Isotopes useful?
Understanding Isotopes explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Isotopes?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Isotopes?
Related topics in Physics include Nuclear Fission and Fusion, Orbits and Satellites, Simple Harmonic Motion and Pendulums.