in the nucleus
The symbol represents an electron whose charge corresponds to and since it has no nucleons, . It must be carefully noted that the electron released during beta decay is NOT an orbital electron but an electron whose origin was in the nucleus. The process has one neutron becoming one proton and one electron and the electron being emitted as a beta particle. Since a neutron has been lost AND a proton has been gained, the mass number does not change. The atomic number, however, has increased one due to the gain of a proton. Therefore, as a result of beta decay, the daughter product will have the same mass number as the parent and an atomic number one greater than the parent.