Radionuclide
Summary table for classes of nuclides, "stable" and radioactive

Radionuclide

Section Title: Summary table for classes of nuclides, "stable" and radioactive
Table Section Text: None

Stability class	Number of nuclides	Running total	Notes on running total

Theoretically stable to all but proton decay	90	90	Includes first 40 elements. Proton decay yet to be observed.

Theoretically stable to alpha decay, beta decay, isomeric transition, and double beta decay but not spontaneous fission, which is possible for "stable" nuclides ≥ niobium-93	56	146	All nuclides that are possible completely stable (spontaneous fission has never been observed for nuclides with mass number < 232).

Energetically unstable to one or more known decay modes, but no decay yet seen. All considered "stable" until decay detected.	106	252	Total of classically stable nuclides.

Radioactive primordial nuclides.	34	286	Total primordial elements include uranium, thorium, bismuth, rubidium-87, potassium-40, tellurium-128 plus all stable nuclides.

Radioactive nonprimordial, but naturally occurring on Earth.	61	347	Carbon-14 (and other isotopes generated by cosmic rays) and daughters of radioactive primordial elements, such as radium, polonium, etc. 41 of these have a half life of greater than one hour.

Radioactive synthetic half-life ≥ 1.0 hour). Includes most useful radiotracers.	662	989	These 989 nuclides are listed in the article List of nuclides.

Radioactive synthetic (half-life < 1.0 hour).	>2400	>3300	Includes all well-characterized synthetic nuclides.

Sentence(s)

This is a summary table for the 989 nuclides, with half-lives longer than one hour, given in list of nuclides.

final_sentence: This is a summary table for the 989 nuclides, with half-lives longer than one hour, given in list of nuclides.