Atoms emit alpha particles during alpha radiation. An imbalance between the number of protons and neutrons inside an atom's nucleus results in the emission of alpha particles.
Ernest Rutherford first saw alpha particles in 1899 as a result of uranium experimentation. Alpha particles consist of two protons and two neutrons, the same as a helium nucleus. Alpha particles are natural substances that show up naturally in the Earth's crust.
The emission of alpha particles helps keep balance between protons and neutrons while a substance undergoes radioactive decay. As the number of protons decides the makeup of an element, whenever an atom jettisons an alpha particle, the atom becomes a different element.