Answer is:
the emitted particle is an alpha particle.
Nuclear reaction: ¹⁶O + p⁺
→ ¹³N + α (alpha particle).
Alpha decay is radioactive decay in which an atomic nucleus emits
an alpha particle (helium nucleus) and transforms into an atom
with an atomic number that is reduced by two and mass
number that is reduced by four.
When oxygen-16 gain one proton, atomic mass is 17, but when lose alpha particle
atomic mass reduces by four to 13.
