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The tables of elements are sorted in order of decreasing number of nuclides associated with each element. (For a list sorted entirely in terms of half-lives of nuclides, with mixing of elements, see List of nuclides.) Stable and unstable (marked decays) nuclides are given, with symbols for unstable (radioactive) nuclides in italics. Note that ...
7 elements have 6 stable isotopes apiece; 11 elements have 5 stable isotopes apiece; 9 elements have 4 stable isotopes apiece; 5 elements have 3 stable isotopes apiece; 16 elements have 2 stable isotopes apiece; 26 elements have 1 single stable isotope. These last 26 are thus called monoisotopic elements. [3] The mean number of stable isotopes ...
More strongly, if is Lyapunov stable and all solutions that start out near converge to , then is said to be asymptotically stable (see asymptotic analysis). The notion of exponential stability guarantees a minimal rate of decay, i.e., an estimate of how quickly the solutions converge.
This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
There are 26 such elements, as listed. Stability is experimentally defined for chemical elements, as there are a number of stable nuclides with atomic numbers over ~ 40 which are theoretically unstable, but apparently have half-lives so long that they have not been observed either directly or indirectly (from measurement of products) to decay.
"The first part of the list contain 80 of the first 82 elements in the periodic table" This statement implies that within the first 82 elements, there are two that are unstable. However, it isn't explained to the reader until the diagram that these are technetium and promethium.
A consequence of this rule is that technetium and promethium both have no stable isotopes, as each of the neighboring elements on the periodic table (molybdenum and ruthenium, and neodymium and samarium, respectively) have a beta-stable isotope for each mass number for the range in which the isotopes of the unstable elements usually would be stable to beta decay.
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...