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Additionally, about 31 nuclides of the naturally occurring elements have unstable isotopes with a half-life larger than the age of the Solar System (~10 9 years or more). [b] An additional four nuclides have half-lives longer than 100 million years, which is far less than the age of the Solar System, but long enough for some of them to have ...
The mechanism for the creation of a synthetic element is to force additional protons into the nucleus of an element with an atomic number lower than 95. All known (see: Island of stability) synthetic elements are unstable, but they decay at widely varying rates; the half-lives of their longest-lived isotopes range from microseconds to millions ...
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive .
All the first 66 elements, except 43, 61, 62, and 63. If spontaneous fission is possible for the nuclides with mass numbers ≥ 93, then all such nuclides are unstable, so that only the first 40 elements would be stable. If protons decay, then there are no stable nuclides. Energetically unstable to one or more known decay modes, but no decay ...
This page lists radioactive nuclides by their half-life.
The discoverers of plutonium (element 94) considered naming it "ultimium", thinking it was the last. [18] Following the discoveries of heavier elements, of which some decayed in microseconds, it then seemed that instability with respect to spontaneous fission would limit the existence of heavier elements.
Energetically unstable to one or more known decay modes, but no decay yet seen. All considered "stable" until decay detected. 105 251 Total of classically stable nuclides. Radioactive primordial nuclides. 35 286 Total primordial elements include uranium, thorium, bismuth, rubidium-87, potassium-40, tellurium-128 plus all stable nuclides.
This is an accepted version of this page This is the latest accepted revision, reviewed on 5 March 2025. Theoretical chemical element with atomic number 119 (Uue) Ununennium, 119 Uue Theoretical element Ununennium Pronunciation / ˌ uː n. uː n ˈ ɛ n i ə m / ⓘ (OON -oon- EN -ee-əm) Alternative names element 119, eka-francium Ununennium in the periodic table Hydrogen Helium Lithium ...