Year 11 - Science
Unstable nuclei
Nuclear physics
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit covers atomic structure, isotopes, radioactive decay, and half-life. It explores alpha, beta, and gamma radiation, nuclear fission and fusion, and the uses of radiation in medicine, highlighting differences between contamination and irradiation.
Lesson Summary
You will learn to explain why some nuclei are stable and why some are unstable.
Key Notes
- Protons have a positive electric charge of +1 and a mass number of 1.
- Neutrons have no electric charge and have a mass number of 1.
- The atomic number of an element equals the number of protons in the nucleus of each atom of that element.
- The atomic number of an element equals the number of electrons in each atom of that element.
- Atoms of an element that have different numbers of neutrons in their nuclei are isotopes of the element.
Vocabulary To Learn
- nucleus: the central part of an atom which contains protons and neutrons
- nucleon: the term for particles in a nucleus (protons and neutrons)
- atomic (proton) number: the number of protons within a particular nucleus
- mass (nucleon) number: the total number of nucleons within a particular nucleus (protons + neutrons)
- isotopes: atoms of the same element with differing numbers of neutrons
Common Mistakes To Avoid
- Many pupils are uncertain about the forces attracting or repelling particles inside an atom.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
Protons have a positive electric charge of +1 and a mass number of 1. Neutrons have no electric charge and have a mass number of 1.
2. Define this scientific word and use it in context. 'nucleus'
the central part of an atom which contains protons and neutrons. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Many pupils are uncertain about the forces attracting or repelling particles inside an atom. Correction: Extend explanations to include electrostatic forces between protons in the nucleus and introduce the strong nuclear force to explain why nuclei do not self destruct.
More Lessons In This Unit
- Activity and half-life calculations Study Guide
- Activity and half-life calculations (including complex ones) Study Guide
- Evidence of atomic structure Study Guide
- Ionising radiation Study Guide
- Nuclear decay Study Guide
- Nuclear decay (including beta–plus) Study Guide
- Nuclear fission and fusion Study Guide
- Nuclear power Study Guide
- Nuclear power stations Study Guide
- Radioactive half-life Study Guide
- Uses of radiation Study Guide
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