Answer:
Aluminium-28
Explanation:
The decay can be with particles alfa (α), beta (β) or gamma radiation (γ). The particle alfa has mass 4 and charge +2, so when the decay occurs by it, the atom will lose two protons and 4 mass unity. The radiation gamma has no mass or charge.
The beta particle has no mass, and charge -1. When this phenomenon happens, a neutron decomposes into a proton, an electron, and an antineutrino(which has no mass or charge). The electron is the beta particle. So the mass of the atom continues the same (because of the proton gained), and it gains a proton, so its atomic number changes for +1.
The magnesium-28 beta decay occurs by:
²⁸Mg₁₂ ⇒ ⁰β₋₁ + ²⁸Al₁₃
