Atomic Structure

What is Atomic Structure?

Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Atomic Structure. 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 Atomic Structure in your own words and give one example from everyday life. If you can do that, you have understood the core idea.

Understanding Atomic Structure explains how the physical world behaves, from sport and transport to electricity and medicine.

Atomic Structure in detail

An atom has a tiny, dense nucleus containing protons (positive) and neutrons (neutral), surrounded by electrons (negative) in shells. The atom is mostly empty space, and it is neutral because the number of protons equals the number of electrons.

The atomic number is the number of protons and the mass number is protons plus neutrons. Rutherford's alpha scattering experiment showed that the positive charge is concentrated in a small nucleus, replacing the earlier plum pudding model. Bohr then described electrons in fixed energy levels. Understanding atomic structure is the foundation for chemistry and nuclear physics.

How the interactive helps you understand Atomic Structure

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 Atomic Structure.

Real-life uses and examples

• Explain everyday devices, such as brakes, lifts or chargers, using Atomic Structure.
• Use Atomic Structure to make sense of a practical and its results.
• Answer “explain” questions by linking Atomic Structure to a clear cause and effect.

Common mistakes to avoid

• Forgetting that some quantities, such as force or velocity, also have a direction.
• Mixing up Atomic Structure with a related quantity that has different units.
• Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.