Key Stage 4
Meaning
An alpha particle is a type of ionising radiation made of 2 protons and 2 neutrons emitted from the nucleus of an unstable isotope.
About Alpha Particles
- Alpha particles may also be referred to as alpha radiation.
- Alpha particles are a Helium nucleus.
- Alpha particles have a relative atomic mass of 4 and relative charge of +2.
- Alpha particles are emitted when a nucleus is too large or the ratio of protons to neutrons is too large.
- Alpha particles are emitted rather than single protons or neutrons because the Helium nucleus is extremely stable.
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Scientist were able to determine the charge and mass of alpha particle by sending it between two electrically charged plates and observing its path.
The alpha particle moves towards the negative plate, so it must be positively charged. The rate of curvature depends on the mass:charge ratio which indicates it has a relative atomic mass of 4 and relative charge of +2. |