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In contrast, the proton numbers for which there are no stable isotopes are 43, 61, and 83 or more (83, 90, 92, and perhaps 94 have primordial radionuclides). [3] This is related to nuclear magic numbers , the number of nucleons forming complete shells within the nucleus, e.g. 2, 8, 20, 28, 50, 82, and 126.
A chart or table of nuclides maps the nuclear, or radioactive, behavior of nuclides, as it distinguishes the isotopes of an element.It contrasts with a periodic table, which only maps their chemical behavior, since isotopes (nuclides that are variants of the same element) do not differ chemically to any significant degree, with the exception of hydrogen.
Radioactive isotope table "lists ALL radioactive nuclei with a half-life greater than 1000 years", incorporated in the list above. The NUBASE2020 evaluation of nuclear physics properties F.G. Kondev et al. 2021 Chinese Phys. C 45 030001. The PDF of this article lists the half-lives of all known radioactives nuclides.
The Mattauch isobar rule states that if two adjacent elements on the periodic table have isotopes of the same mass number, at least one of these isobars must be a radionuclide (radioactive). In cases of three isobars of sequential elements where the first and last are stable (this is often the case for even-even nuclides, see above ), branched ...
The term isotopes (originally also isotopic elements, [4] now sometimes isotopic nuclides [5]) is intended to imply comparison (like synonyms or isomers). For example, the nuclides 12 6 C, 13 6 C, 14 6 C are isotopes (nuclides with the same atomic number but different mass numbers [6]), but 40 18 Ar, 40 19 K, 40 20 Ca are isobars (nuclides with ...
Stable even–even nuclides number as many as three isobars for some mass numbers, and up to seven isotopes for some atomic numbers. Conversely, of the 251 known stable nuclides, only five have both an odd number of protons and odd number of neutrons: hydrogen-2 ( deuterium ), lithium-6 , boron-10 , nitrogen-14 , and tantalum-180m .
An example is the two states of the single isotope 99 43 Tc shown among the decay schemes. Each of these two states (technetium-99m and technetium-99) qualifies as a different nuclide, illustrating one way that nuclides may differ from isotopes (an isotope may consist of several different nuclides of different excitation states).
The Mattauch isobar rule, formulated by Josef Mattauch in 1934, states that if two adjacent elements on the periodic table have isotopes of the same mass number, one of the isotopes must be radioactive. [1] [2] Two nuclides that have the same mass number can both be stable only if their atomic numbers differ by more than one.