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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 ...
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.)
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 ...
Side view of a 1.5 to 2.5 inches (38 to 64 mm) adapter. National Hose thread (NH), also known as National Standard Thread (NST). It is the most common type of fire hose coupling used in the United States. The male and female straight (non-tapered) threads screw together and the connection is sealed with a gasket.
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 ...
Potassium-40 is especially important in potassium–argon (K–Ar) dating. Argon is a gas that does not ordinarily combine with other elements. So, when a mineral forms – whether from molten rock , or from substances dissolved in water – it will be initially argon-free, even if there is some argon in the liquid.
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]
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.