$X Z A → Y Z+1 A + e −1 0$
3. During a beta decay, a radioactive atom X decay and emits a beta particle ($e$ ).
4. One of the neutron is disintegrated to become proton and electron. The electron is emitted out from the nucleus whereas the proton stay in the nucleus. $n 0 1 → p 1 1 + e −1 0$
$T 90 234 h→ P 91 234 a+ e −1 0 P 82 210 b→ B 83 210 i+ e −1 0 B 4 11 e→ B 5 11 + e −1 0 F 26 59 e→ C 27 59 o+ e −1 0 N 11 24 a→ M 12 24 g+ e −1 0$