Symbol- Each element is assigned a chemical symbol.
For example, if you took a container of the element hydrogen (H), 99.984% of it would be H-1, 0.0156% of it would be H-2, and 0% of the hydrogen would be H-3.
This is because both the protons and the neutrons in an atom have a relatively equal mass.
The mass of an electron is so insignificant that it is not represented in the atomic mass.
These three kinds of radiation have very different properties in some respects but are all ionizing radiation–each is energetic enough to break chemical bonds, thereby possessing the ability to damage or destroy living cells.
Uranium-238, the most prevalent isotope in uranium ore, has a half-life of about 4.5 billion years; that is, half the atoms in any sample will decay in that amount of time.