Isotopes
Sixteen isotopes of mendelevium from mass 245 to 260 have been characterized, with the most stable being 258Md with a half-life of 51.5 days, 260Md with a half-life of 31.8 days, and 257Md with a half-life of 5.52 hours. All of the remaining radioactive isotopes have half-lives that are less than 97 minutes, and the majority of these have half-lives that are less than 5 minutes. This element also has 5 meta states, with the longest-lived being 258mMd (t½ = 58 minutes). The isotopes of mendelevium range in atomic weight from 245.091 u (245Md) to 260.104 u (260Md).
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