an example of nuclides made by nuclear reactions, are cosmogenic ([[radiocarbon]]) that is made by [[cosmic ray]] bombardment of other elements, and nucleogenic which is still being created by neutron bombardment of natural as a result of natural fission in uranium ores. cosmogenic nuclides may be either stable or radioactive. if they are stable, their existence must be deduced against a background of stable nuclides, since every known stable nuclide is present on earth primordially.