Evidence of atomic structure
I can describe how alpha particles were used to show the size and nature of atomic nuclei.
Evidence of atomic structure
I can describe how alpha particles were used to show the size and nature of atomic nuclei.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Background radiation is caused by unstable nuclei that are around us all of the time.
- Atoms are very small with a radius of about 1 × 10⁻¹⁰ m.
- The alpha particle scattering experiment (Rutherford, 1909) provides evidence for the size and nature of atomic nuclei.
- An atomic nucleus has a radius about 10 000 times smaller than that of an atom.
- Most of the mass of an atom is in its nucleus.
Keywords
Background radiation - the radiation in the surroundings of a particular place
Alpha particle - a small, positively charged particle which was used to discover the nucleus
Alpha scattering experiment - the experiment used to discover the atomic nucleus from the deflection of alpha particles fired at it
Nucleus - the central part of an atom which contains most of the mass and all of the positive charge
Common misconception
Atoms are visible under powerful optical microscopes.
Emphasise that atoms are far too small to see and our descriptions of atoms are models, based on evidence, that help us understand how they behave.
To help you plan your year 11 physics lesson on: Evidence of atomic structure, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 11 physics lesson on: Evidence of atomic structure, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 4 physics lessons from the Nuclear physics unit, dive into the full secondary physics curriculum, or learn more about lesson planning.
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Supervision
Adult supervision recommended
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Lesson video
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Starter quiz
6 Questions
electron -
negatively charged particle found outside a nucleus
proton -
positively charges particle found in a nucleus
neutron -
particle with no charge found in a nucleus
atom -
neutral particle
Exit quiz
6 Questions
background radiation -
the radiation in the surroundings at a particular place
alpha particle -
a positively charged particle that is a type of radiation
alpha scattering experiment -
an investigation to explore the structure of atoms
nucleus -
the part in the middle of an atom which contains most of its mass
most pass straight through -
most of an atom is empty space
some are deflected by large angles -
there is a nucleus with a positive charge
a small number ‘bounce back’ -
the nucleus contains most of the mass of the atom