Explain `alpha`- decay ?

Explanation

1. It is the phenomenon of emission of an `alpha` particle from a radioactive nucleus. When a nucleus emits an alpha particle, its mass number decreases by 4 and charge number decreases by 2.
2. In general, alpha decay is represented as
`._(Z)X^(A) rarr ._(Z-2)Y^(A-4)+ ._(2)He^(4)+Q`
Where Q is the energy released in the decay.
3. Thus the total mass energy of the decay products is less than the mass energy of the original nuclide.
4. The difference between the initial mass energy and the total mass energy of decay products is called disintegration energy (Q) of the process.
5. This can be calculated using Einstein's mass energy equivalence relation, `E = (Delta m). c^(2)`
i.e., `Q=(m_(x)-m_(y)-m_(He))c^(2)`
The energy released (Q) is shared by daughter nucleus y and alpha particle.