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Encyclopedia > Electron capture

Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom, and there isn't enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron emission. If the energy difference between the parent atom and the daughter one is less than 1.022 MeV, positron emission is forbidden and electron capture is the sole decay mode. For example, Rubidium-83 will decay to Krypton-83 solely by electron capture (the energy difference is about 0.9 MeV). The R process (R for rapid) is a neutron capture process for radioactive elements which occurs in high neutron density, high temperature conditions. ... The S process (S for slow) is a neutron capture process in the decay of radioactive elements that occurs in lower neutron density, lower temperature conditions. ... The p process was believed to be a proton capture process which occurrs during supernovae explosions. ... In physics, the decay mode describes a particular way a particle decays. ... // Isotopes are forms of an element whose nuclei have the same atomic numberâ€“-the number of protons in the nucleus--but different mass numbers because they contain different numbers of neutrons. ... Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... A stylized representation of a lithium atom. ... Properties An atom (Greek Î¬Ï„Î¿Î¼Î¿Î½ from Î¬: non and Ï„Î¿Î¼Î¿Î½: divisible) is a submicroscopic structure found in all ordinary matter. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ...

In this case, one of the orbital electrons, usually from the K or L electron shell (K-electron capture, also K-capture, or L-electron capture, L-capture), is captured by a proton in the nucleus, forming a neutron and a neutrino. Since the proton is changed to a neutron, the number of neutrons increases by 1, the number of protons decreases by 1, and the atomic mass number remains unchanged. By changing the number of protons, electron capture transforms the nuclide into a new element. The atom ends up in excited state, with a missing electron in inner shell. The atom in its excited state will emit X-rays (a type of electromagnetic radiation) or/and Auger electrons. The electron in an outer shell fall in to the inner shell releacing energy, emitted as the x-ray. because of this electron capture is most likely to happen in larger neculides. Properties The electron is a fundamental subatomic particle that carries a negative electric charge. ... In atomic physics, an electron shell is a group of atomic orbitals with the same value of the principal quantum number n. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... The neutrino is an elementary particle. ... The atomic mass of a chemical element (also known as the relative atomic mass or average atomic mass or atomic weight) is the average atomic mass of all the chemical elements isotopes as found in a particular environment, weighted by isotopic abundance. ... Isotopes are atoms of a chemical element whose nuclei have the same atomic number, Z, but different atomic weights, A. The word isotope, meaning at the same place, comes from the fact that isotopes are located at the same place on the periodic table. ... A chemical element, often called simply element, is a chemical substance that cannot be divided or changed into other chemical substances by any ordinary chemical technique. ... In quantum mechanics, an excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum). ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Electromagnetic radiation can be conceptualized as a self propagating transverse oscillating wave of electric and magnetic fields. ... When an electron is removed from a core level of an energy. ...

$mathrm{p}^+ + mathrm{e}^- rightarrowmathrm{n} + {nu}_e ,$

examples:

 $mathrm{{}^{26}_{13}Al}+mathrm{e}^- rightarrowmathrm{{}^{26}_{12}Mg}+{nu}_e$ $mathrm{{}^{59}_{28}Ni}+mathrm{e}^- rightarrowmathrm{{}^{59}_{27}Co}+{nu}_e$

It is of note that radioactive isotopes which go by pure electron capture can, in theory, be inhibited from radioactive decay if they are fully ionized ("stripped" is sometimes used to describe such ions). It is hypothesized that such elements, if formed by the r-process in exploding supernovae, are ejected fully ionized and so do not undergo radioactive decay as long as they do not encounter electrons in outer space. Anomalies in elemental distributions are thought to be partly a result of this effect on electron capture. // An ion is an atom or group of atoms with a net electric charge. ... The R process (R for rapid) is a neutron capture process for radioactive elements which occurs in high neutron density, high temperature conditions. ... Multiwavelength X-ray image of the remnant of Keplers Supernova, SN 1604. ...

Results from FactBites:

 Nuclear Science Glossary (1718 words) Nuclear decay by emission of an electron or a positron. Disappearance of a radioactive substance due to nuclear emission of an alpha or beta particle, capture of an atomic electron, neutrinos, spontaneous fission, and the emission of bremsstrahlung, x-rays, and conversion electrons. Nuclear decay by capture of an atomic electron.
 Electron capture (95 words) The nucleus of an atom captures an electron of the atomic shell, whereby a proton in the nucleus converts into a neutron. The formed nuclide has an atomic number which is smaller by one unit; the mass number remains the same. Electron capture; capture of an electron from the nuclear shell of the electron sheath during the disintegration of potassium-40 into argon-40
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