Chemistry / Unit 12 Chem 2513 short lesson, about 20 seconds
Twin: Beta Decay
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The idea
Beta decay emits an electron as a neutron converts to a proton, leaving mass number unchanged while raising atomic number by one.
In practice
Iodine-131 undergoes beta decay to form xenon-131, mass number unchanged but atomic number up by one.
Where people slip
The emitted electron originates from the nucleus, converting a neutron into a proton, not from the atom's electron cloud — easy to conflate.
Your place on the trail
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