Chemical symbols and isotopes of the elements

Name Symbol Atomic number Atomic mass occurring isotopes1 Radioactive isotopes 

Name Symbol number mass isotopes1 Radioactive isotopes 

Name Atomic Symbol number Atomic mass Naturally occurring isotopes1 Radioactive isotopes 

Not all naturally occurring isotopes are stable - some are radioactive but with long half-lives. See (for example) WebElements [http //www.webelements.com/webelements/index. html] for abundance ratios of naturally occurring isotopes and half-lives of radioisotopes. 

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