Isotope

Isotopes of a chemical element are atoms whose nuclei have different numbers of neutrons. The name, meaning at the same place, reffers to the location on the same place of the periodic table. Having the same number of proton, they also have the same number of electrons, what makes their chemical properties almost identical.

Different isotopes of an element are created on stars, by bombardment by [cosmic ray]?s on earth, and by [nuclear decay]? of other elements.