Answer:
A neutron changes into a proton or a proton changes into a neutron
Step-by-step explanation:
Here, we want to know what happens during a beta decay
In a beta decay, we have a conversion in the nucleus of an atom
Generally, there must be an excess of either the proton or a neutron in the nucleus of a radioactive atom
What we are saying here is that both do not have same values
Hence, what we have is that during a beta decay, there is a transformation of a proton to a neutron or a neutron to a proton, depending on which of the two are in excess
What this mean is that the one that changes to the other is largely dependent on which of the two is more than the other
That brings us to the principle of having a beta positive decay or a beta negative decay