Alpha particle emission is a type of radioactive decay in which an unstable atomic nucleus releases an alpha particle. An alpha particle is composed of 2 protons and 2 neutrons, effectively making it equivalent to a helium-4 nucleus.
When an atom undergoes alpha decay, the following changes occur:
-
Decrease in Atomic Number: The emission of an alpha particle reduces the atomic number of the original atom by 2. This means that the atom transforms into a different element, located two places to the left on the periodic table.
-
Decrease in Mass Number: The mass number, which is the total number of protons and neutrons in the nucleus, decreases by 4, since 2 protons and 2 neutrons are lost in the alpha particle. This change alters the identity and properties of the atom.
For example, if Uranium-238 (which has 92 protons and a mass number of 238) undergoes alpha decay, it will emit an alpha particle and transform into Thorium-234 (which has 90 protons and a mass number of 234).
Overall, alpha particle emission results in the formation of a new element that has different chemical properties and characteristics compared to the original atom. This process is an important aspect of nuclear physics and plays a significant role in the behavior of heavy elements and their isotopes.