Editing Stable nuclide (section)

== Summary table for numbers of each class of nuclides ==

This is a summary table from [[List of nuclides]]. Numbers are not exact and may change slightly in the future, as nuclides are observed to be radioactive, or new half-lives are determined to some precision.

{| class="wikitable sortable"  style="max-width:1120px;" |
! class="unsortable" | Type of nuclide by stability class
! style="max-width:50px;" | Number&nbsp;of nuclides in class
! style="max-width:110px;" | Running&nbsp;total of nuclides in all classes to this point
! class="unsortable" | Notes
|-
| Theoretically stable according to known decay modes, including [[alpha decay]], [[beta decay]], [[isomeric transition]], and [[double beta decay]]
| style="text-align:right;" | 146
| style="text-align:right;" | 146
|All the first 66 elements, except [[technetium]], [[promethium]], [[samarium]], and [[europium]]. If [[spontaneous fission]] is possible for the nuclides with [[mass number]]s ≥ 93, then all such nuclides are unstable, so that only the first 40 elements would be stable. If [[Proton decay|protons decay]], then there are no stable nuclides.
|-
| Energetically unstable to one or more known decay modes, but no decay yet seen. Considered stable until radioactivity confirmed.
| style="text-align:right;" | 105<ref name="bellidecay"/><ref name="Tretyak2002"/>
| style="text-align:right;" | 251
| Total is the observationally stable nuclides. All elements up to [[lead]] (except [[technetium]] and [[promethium]]) are included.
|-
| Radioactive [[primordial nuclide]]s.
| style="text-align:right;" | 35
| style="text-align:right;" | 286
| Includes [[bismuth]], [[thorium]], and [[uranium]]
|-
| Radioactive nonprimordial, but occur naturally on Earth.
| style="text-align:right;" | ~61 significant
| style="text-align:right;" | ~347 significant
| [[Cosmogenic nuclide]]s from cosmic rays; daughters of radioactive primordials such as [[francium]], etc.
|-
|}