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The darker more stable isotope region departs from the line of protons (Z) = neutrons (N), as the element number Z becomes larger. This is a list of chemical elements by the stability of their isotopes. Of the first 82 elements in the periodic table, 80 have isotopes considered to be stable. [1] Overall, there are 251 known stable isotopes in ...
The single monoisotopic exception to the odd Z rule is beryllium; its single stable, primordial isotope, beryllium-9, has 4 protons and 5 neutrons. This element is prevented from having a stable isotope with equal numbers of neutrons and protons ( beryllium-8 , with 4 of each) by its instability toward alpha decay , which is favored due to the ...
In chemistry, chemical stability is the thermodynamic stability of a chemical system, in particular a chemical compound or a polymer. [1]Chemical stability may also refer to the shelf-life of a particular chemical compound; that is the duration of time before it begins to degrade in response to environmental factors.
The 251 known stable nuclides include tantalum-180m, since even though its decay is automatically implied by its being "metastable", this has not been observed. All "stable" isotopes (stable by observation, not theory) are the ground states of nuclei, except for tantalum-180m, which is a nuclear isomer or excited state. The ground state ...
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. Three of the most common types of decay are alpha, beta, and gamma decay.
3 He is the only stable isotope other than 1 H with more protons than neutrons. (There are many such unstable isotopes; the lightest are 7 Be and 8 B.) There is only a trace (~2ppm) [16] of 3 He on Earth, mainly present since the formation of the Earth, although some falls to Earth trapped in cosmic dust. [7]
Hydrogen (1 H) has three naturally occurring isotopes: 1 H, 2 H, and 3 H. 1 H and 2 H are stable, while 3 H has a half-life of 12.32(2) years. [3] [nb 1] Heavier isotopes also exist; all are synthetic and have a half-life of less than 1 zeptosecond (10 −21 s). [4] [5] Of these, 5 H is the least stable, while 7 H is the most.
The stable nuclides have high binding energy, and these nuclides lie along the bottom of the valley of stability. Nuclides with weaker binding energy have combinations of N and Z that lie off of the line of stability and further up the sides of the valley of stability. Unstable nuclides can be formed in nuclear reactors or supernovas, for