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In atomic physics, even–even (EE) nuclei are nuclei with an even number of neutrons and an even number of protons. Even-mass-number nuclei, which comprise 151/251 = ~60% of all stable nuclei, are bosons, i.e. they have integer spin. The vast majority of them, 146 out of 151, belong to the EE class; they have spin 0 because of pairing effects. [1]
An even number of protons or neutrons is more stable (higher binding energy) because of pairing effects, so even–even nuclides are much more stable than odd–odd. One effect is that there are few stable odd–odd nuclides: in fact only five are stable, with another four having half-lives longer than a billion years.
Among the 41 even-Z elements that have a stable nuclide, only two elements (argon and cerium) have no even–odd stable nuclides. One element (tin) has three. There are 24 elements that have one even–odd nuclide and 13 that have two even–odd nuclides. The lightest example of this type of nuclide is 3 2 He and the heaviest is 207 82 Pb.
The 146 even-proton, even-neutron (EE) nuclides comprise ~58% of all stable nuclides and all have spin 0 because of pairing. There are also 24 primordial long-lived even-even nuclides. As a result, each of the 41 even-numbered elements from 2 to 82 has at least one stable isotope, and most of these elements have several primordial isotopes ...
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 .
A set of nuclides with equal proton number (atomic number), i.e., of the same chemical element but different neutron numbers, are called isotopes of the element. Particular nuclides are still often loosely called "isotopes", but the term "nuclide" is the correct one in general (i.e., when Z is not fixed).
The colors of the cells represent the stability of the nuclides. This templates main purpose is to show the patterns that are formed when plotting the stability of the nuclides To that end it is possible to only show even or odd nuclides (or even every fourth nuclide) For general help on using templates see Help:Template#Template usage
In theory, no two stable nuclides have the same mass number (since no two nuclides that have the same mass number are both stable to beta decay and double beta decay), and no stable nuclides exist for mass numbers 5, 8, 143–155, 160–162, and ≥ 165, since in theory, the beta-decay stable nuclides for these mass numbers can undergo alpha decay.