Posted in Physics Revision

Alpha, Beta and Gamma Radiation

Radioactive radiation is dangerous because it is ionising.

An unstable nucleus (one with too many protons or neutrons) can emit alphabeta, or gamma radiation. They do this in order to achieve stability.


  Alpha Beta Gamma
Description 2 neutrons, 2 protons (helium nuclei – not atom) High energy electron High enery electromagnetic radiation
Electric Charge +2 -1 0
Relative Atomic Mass 4   0
Penetration Power Stopped by paper/ few cm of air Stopped by a few mm of aluminium Reduced by several cm of lead or several metres of concrete.
Ionisation Effect Strongly ionising (has a lot of power due to its large mass) Weakly ionising Very weakly ionising
Effects of magnetic/ electric field Weakly affected (due to relatively large mass) Strongly deflected No deflection (no charge)
Effect on nucleus when this decay occurs Alpha decay: 2 neutrons and 2 protons emitted, so atomic mass decreases by 4, atomic number decreases by 2, and energy is released Beta decay: a high energy electron is emitted, so the atomic mass stays the same, and the atomic number decreases by one Gamma emission: high energy electromagnetic radiation is emitted, so the nucleus changes into a more stable shape. Both atomic mass and atomic number stays the same.
Image result for atomic number and mass number of elements uk
Source Just so you can visualise how the numbers will change as each of the decays occur

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