Beta decay, or beta particle emission involves the release of a fast-moving electron, but this does not come from the energy shells populated by the atom's electrons. This is the "creation" of a "new" electron caused by the decay of a neutron into a proton.


By now you already know that a neutron has roughly the same mass as a proton but carries no charge, but a proton carries a positive charge. How, therefore can a neutral particle turn into a positively charged particle?


The nuclear physics behind this very complicated, but it can be looked at as the subtraction of -1. You remember from your mathematics that if you take -1 away from something, you effectively add +1 :



If you take a particle which is neutral, and remove a negative charge from it, you will be left with a particle with a positive charge. Beta decay works in the same way, a neutral (0 charge) neutron decays into a proton which has a unit positive charge by the expulsion of an electron and an anti-neutrino. Don't worry too much about the antineutrino, just think about the simple arithmetic shown by the formula above and you'll be okay.



This rather strange looking expression simply shows an element X with a mass number A and atomic number Z decaying by beta (negative) emission into an isotope of the next higher element X' with the ejection of an electron and an antineutrino. This is all I'm going to say about this particular particle as this is taking us into deeper water, well outside the scope of GCSE.


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