Answer: Alpha particle
Step-by-step explanation:
Alpha decay is defined as the decay process in which a heavier nucleus decays into a lighter nuclei. This decay process releases alpha particle which is also known as helium nucleus.
Alpha particle released carries a mass of 4 units and a charge of +2 units. The alpha particle is also known as helium atom.
In this decay, the atomic number of the atom released gets reduced by 2 units and atomic mass is reduced by 4 units as helium contains 2 protons and 2 neutrons as atomic number is 2 and mass number is 4.
The chemical equation for the alpha decay process is given as:
