Stable isotopes are non-radioactive forms of atoms. Although they do not emit radiation, their unique properties enable them to be used in a broad variety of applications, including water and soil ...

Uranium (chemical symbol U) is a naturally occurring radioactive element ... and specific activity. The half life of a radioactive isotope is the time taken for it to decay to half of its original ...

textrm{N}\) and \(_{6}^{14}\textrm{C}\) are not isotopes. They have the same mass number, A, but different atomic number, Z, and different chemical symbol - they are not the same element.