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There are no stable nuclides with mass numbers 5 or 8. There are stable nuclides with all other mass numbers up to 208 with the exceptions of 147 and 151, which are represented by the very long-lived samarium-147 and europium-151. (Bismuth-209 was found to be radioactive in 2003, but with a half-life of 2.01 × 10 19 years.)
The radioactive dosage from consuming one banana is around 10 −7 sievert, or 0.1 microsievert, under the assumptions that all of the radiation produced by potassium-40 is absorbed in the body (which is mostly true, as the majority of the radiation is beta-minus radiation, which has a short range) and that the biological half life of potassium ...
Conversely, of the 251 known stable nuclides, only five have both an odd number of protons and odd number of neutrons: hydrogen-2 , lithium-6, boron-10, nitrogen-14, and tantalum-180m. Also, only four naturally occurring, radioactive odd–odd nuclides have a half-life >10 9 years: potassium-40, vanadium-50, lanthanum-138, and lutetium-176.
All other potassium isotopes have half-lives under a day, most under a minute. The least stable is 31 K, a three-proton emitter discovered in 2019; its half-life was measured to be shorter than 10 picoseconds. [5] [6] Stable potassium isotopes have been used for several nutrient cycling studies since potassium is a macronutrient required for ...
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 ...
Except 20, 50 and 82 (all these three numbers are magic numbers), all other neutron numbers have at most 4 stable nuclides (in the case of 20, there are 5 stable nuclides 36 S, 37 Cl, 38 Ar, 39 K, and 40 Ca, and in the case for 50, there are 5 stable nuclides: 86 Kr, 88 Sr, 89 Y, 90 Zr, and 92 Mo, and 1 radioactive primordial nuclide, 87 Rb).
Since the nuclei that can readily undergo fission are particularly neutron-rich (e.g. 61% of the nucleons in uranium-235 are neutrons), the initial fission products are often more neutron-rich than stable nuclei of the same mass as the fission product (e.g. stable zirconium-90 is 56% neutrons compared to unstable strontium-90 at 58%).
Neutral potassium atoms have 19 electrons, one more than the configuration of the noble gas argon. Because of its low first ionization energy of 418.8 kJ/mol, the potassium atom is much more likely to lose the last electron and acquire a positive charge, although negatively charged alkalide K − ions are not impossible. [23]