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Isotopes of mendelevium

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Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionJun 9, 2026
Entity authorityQ469744 ↗
Source-derived summary

Mendelevium (101Md) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 256Md (which was also the first isotope of any element produced one atom at a time) in 1955. There are 17 known radioisotopes, ranging in atomic mass from 244Md to 260Md, and 10 isomers. The longest-lived isotope is 258Md with a half-life of 51.6 days, and the longest-lived isomer is 258mMd with a half-life of 57 minutes.

List of isotopes

References

Isotope masses from:

M. Wang; G. Audi; A. H. Wapstra; F. G. Kondev; M. MacCormick; X. Xu; et al. (2012). "The AME2012 atomic mass evaluation (II). Tables, graphs and references" (PDF). Chinese Physics C. 36 (12): 1603–2014.

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The public source identifies “Isotopes of mendelevium” as open-knowledge reference entry. This brief keeps that definition visible, then builds a research path around Isotopes, mendelevium and Open-knowledge.

Editorial reviewA concise reference frame for defining the subject, testing terminology and identifying the institution closest to the evidence. The current lead gives the account dated anchors—1955, 2012, 1603, 2014—that can be checked directly. The selected authority fields contribute no independent date. Its value is orientation rather than verdict, with Isotopes, mendelevium and Open-knowledge providing the first useful test.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Jun 9, 2026. The linked authority identifier is Q469744. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1955, 2012, 1603 and 2014.

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Source & attribution

This entry incorporates text from “Isotopes of mendelevium” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.