The isotopes any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in the nucleus, or different atomic weights. There are 275 isotopes of the 81 stable elements, in addition to over 800 radioactive isotopes, and every element has known isotopic forms. Isotopes of a single element possess almost identical properties.
Thhe life span of the isotopes
This do not age is that their of desintegration is constant in time,the number of atoms shows that they desintegraten in a time interval wich dt is proportional to the atom of atoms that has not been dessintegrated and this has a conclusion that all atom iin the sample on parts enters have possibility of desintegrating.
