Identify alpha beta-minus and gamma emissions
Name their physical nature and charge without treating nuclear beta electrons as pre-existing orbital electrons.
Mapped to the named 0654 section using teaching from the corresponding single-science course. A 0654-specific review of every Core and Supplement objective is still in progress. Written practice is self-checked; it does not demonstrate supervised laboratory competence or award an official Cambridge grade.
Before you begin
- Know nucleus and electron regions.
- Use relative particle charges.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which emission is electromagnetic radiation?
What you will learn
- Name their physical nature and charge without treating nuclear beta electrons as pre-existing orbital electrons.
- Identify the three specified emissions and preserve the selected beta-minus scope.
Name what leaves the nucleus
An alpha particle is a helium nucleus containing two protons and two neutrons: it has relative charge +2. In this syllabus beta means beta-minus, a high-speed electron emitted in a nuclear change with relative charge −1. Beta-plus emission is not included in the selected requirement.
Gamma radiation is high-energy electromagnetic radiation emitted from the nucleus. It has no electric charge and is not a proton, neutron or helium nucleus. Its emission can accompany a nuclear change or an excited nucleus losing energy.
Keep origin distinct from charge sign
A beta-minus electron is created in the nuclear process represented in Supplement work by neutron conversion to proton and electron. It is not simply a surrounding atomic electron pulled from an orbit. Electron loss from an atom forms an ion; beta decay changes the nucleus.
The three emissions have different penetrating and ionising behaviour. This lesson identifies their nature and charge; the next compares those effects. Gamma can interact and ionise indirectly even though it is uncharged. No exact energy or range is fixed by the name alone.
Sources for this lesson
Pause and explain
Is beta-minus emission just removal of a pre-existing surrounding electron?
Worked example
Identify the nature and relative charge of alpha, beta-minus and gamma.
Show the worked solution
- Alpha is a helium nucleus with +2 charge.
- Beta-minus is a nuclear-emitted electron with −1.
- Gamma is uncharged electromagnetic radiation.
Answer Alpha: helium nucleus, +2; beta-minus: electron, −1; gamma: uncharged electromagnetic radiation.
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Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
State the constituents and charge of an alpha particle.
Give me a hint
Treat it as a helium nucleus.
Compare my reasoning
- It has two protons.
- It has two neutrons.
- Two proton charges give +2.
2 protons, 2 neutrons; +2 charge.
Look for these in your work
- Exclude surrounding helium electrons.
- Retain the positive charge.
Distinguish beta-minus from gamma by nature and charge.
Give me a hint
Compare an electron with electromagnetic radiation.
Compare my reasoning
- Beta-minus is an electron.
- It has charge −1.
- Gamma is uncharged electromagnetic radiation.
Beta-minus: electron, −1; gamma: electromagnetic radiation, zero charge.
Look for these in your work
- Describe nature and charge.
- Do not call gamma a neutron.
A label describes alpha as a neutral helium atom and beta as an orbital electron simply escaping. Correct both.
Give me a hint
Keep the emitted object and nuclear origin precise.
Compare my reasoning
- Alpha is the helium nucleus, without its balancing electrons.
- Its charge is +2.
- Beta-minus belongs to a nuclear conversion.
Alpha is a +2 helium nucleus; beta-minus is emitted in nuclear conversion.
Look for these in your work
- Correct both descriptions.
- Separate nuclear emission from electron-transfer ionisation.
Common mistakes
- Beta means beta-minus here.
- Nuclear beta emission is not ordinary atom ionisation.
- Gamma is not a nucleon.
What can you explain now?
What does an electron’s relative charge equal?
Compare with the explanation
−1
The beta-minus electron has the same negative relative charge as an electron.
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Make it stick
Identify the three specified emissions and preserve the selected beta-minus scope.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.