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An example is calcium-40, with 20 neutrons and 20 protons, which is the heaviest stable isotope made of the same number of protons and neutrons. Both calcium-48 and nickel-48 are doubly magic because calcium-48 has 20 protons and 28 neutrons while nickel-48 has 28 protons and 20 neutrons. Calcium-48 is very neutron-rich for such a relatively ...
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 ...
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 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.
Strontium-90 is a strong beta emitter with a half-life of 28.8 years. Its fission product yield decreases as the mass of the fissile nuclide increases - fission of 233 U produces more 90 Sr than fission of 239 Pu with fission of 235 U in the middle. A map of 90 Sr contamination around Chernobyl has been published by the IAEA. [1]
A further 10 nuclides, platinum-190, samarium-147, lanthanum-138, rubidium-87, rhenium-187, lutetium-176, thorium-232, uranium-238, potassium-40, and uranium-235 have half-lives between 7.0 × 10 8 and 4.83 × 10 11 years, which means they have experienced at least 0.5% depletion since the formation of the Solar System about 4.6 × 10 9 years ...
the sum of the rest mass of the individual nuclei = 6.015 + 2.014 = 8.029 u; the total rest mass on the two helium-nuclei = 2 × 4.0026 = 8.0052 u; missing rest mass = 8.029 – 8.0052 = 0.0238 atomic mass units. In a nuclear reaction, the total (relativistic) energy is conserved.