The reason positron emission and electron capture have the same effect on the nucleus of an atom is because the resulting atom undergoes nuclear transformation, and the new element will have one less proton and one more neutron than the precursor element. Both of these nuclear changes are interesting, so let's look a bit more closely.
In positron emission (also called beta plus decay), a proton in the nucleus of an atom "changes" into a neutron and a positron is ejected. This results in one less proton in that nucleus (naturally), and the creation of a new element. And because the proton had become a neutron, the nucleus has the same number of nucleons and a similar atomic weight.
In electron capture, a nucleus with "too many" protons will actually "pull in" an electron and take it into its nucleus. This electron will "combine" with a proton, and a neutron will result. This will reduce the number of protons in the nucleus, and the creation of a new element -- just like in positron emission. Links to related questions can be found below.
When an atomic nucleus releases a positron, it has undergone beta plus decay. This nuclear transformation event also will release a neutrino. Use the link below for more information.
It is in beta plus decay that we see the positron emitted from the nucleus. (An electron is emitted in beta minus decay.) Within the nucleus of an unstable atom, a proton transforms into a neutron, and a positron is ejected from the nucleus (along with a neutrino). As the nucleus now has one more proton than it did before, its atomic number just went up by one; it is another element.
There is technically no such thing as positron decay. It's a misnomer. The nuclear decay process wherein a positron is emitted from a decaying nucleus is called positron emission or beta plus decay. A link is provided below that question and its answer.
In beta decay, the nucleus of the atom emits an electron. This is a new electron, not one of the electrons in the electron cloud. This does indeed have the effect of changing a neutron into a proton, because total charge has to be conserved - if a new negative thing exists, there has to be a new positive thing too. But the mass has to stay the same too - conveniently, protons and neutrons have almost the same mass.
The decay of an unstable atom by absorbing a wandering positron into the nucleus, converting a neutron into a proton. One example is how a radioactive form of iodine, 131I, can use positron capture to become xenon, 131Xe. This is a stable, so the conversion is a big help.
Many particles can be emitted from radioactive decay. We have Internal Conversion in which a nucleus transfers the energy to an electron which then releases it. There is also Isometric Transition which is basically the gamma ray (photon). There is the decay in which a nucleon is emitted. In this scenario we can have an alpha decay (in which an alpha particle decays), a proton emission, a neutron emission, double proton emission (two protons are emitted), spontaneous fission (the nucleus brakes down into two smaller nuclei and/or other particles) and we have the cluster decay (where the nucleus emits a smaller nucleus). There is the beta decay too. There is the Beta decay (electron and electron antineutrino are emitted), positron emission (a positron and an electron neutrino are emitted), electron capture (an electron is captured by the nucleus and a neutrino is emitted), bound state beta decay (the nucleus decays to an electron and an antineutrino but here the electron is not emitted since it is captured into a K-shell), double beta decay (two electrons and two antineutrinos are emitted), double electron capture (the nucleus absorbs two electrons and emits two neutrinos), electron capture with positron emission (an electron is absorbed and a positron is emitted along with two neutrinos), and double positron emission (in which the nucleus emits two positrons and two neutrons).
The beta plus decay of mercury (a positron emission event) will deliver the daughter nucleus gold.
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When an atomic nucleus releases a positron, it has undergone beta plus decay. This nuclear transformation event also will release a neutrino. Use the link below for more information.
It is in beta plus decay that we see the positron emitted from the nucleus. (An electron is emitted in beta minus decay.) Within the nucleus of an unstable atom, a proton transforms into a neutron, and a positron is ejected from the nucleus (along with a neutrino). As the nucleus now has one more proton than it did before, its atomic number just went up by one; it is another element.
A nucleus can be inherently unstable. It can absorb an energetic photon (photoactivation) and become unstable. It can capture positrons, electrons, neutrons, and protons and become unstable. Decay processes include: # Alpha emission, a high energy 4He nucleus # Beta emission, a high energy electron # Beta+ emission / Beta capture, either a positron is emitted or an electron is captured into the nucleus (Burp!) # Gamma emission, one or more high energy photons are emitted # Neutron emission, neutrons of varying energies may be ejected in the process of a heavy nucleus decay (even tritium).
A nucleus that starts to decay is called a radioactive nucleus or atom. It decays with a known and unique half life by several processes including but not limited to beta decay, alpha decay, electron capture decay, and positron emission.
There is technically no such thing as positron decay. It's a misnomer. The nuclear decay process wherein a positron is emitted from a decaying nucleus is called positron emission or beta plus decay. A link is provided below that question and its answer.
K capture, a special case of inverse beta decay that doesn't emit a positron (but it does emit an electron neutrino)
In beta decay, the nucleus of the atom emits an electron. This is a new electron, not one of the electrons in the electron cloud. This does indeed have the effect of changing a neutron into a proton, because total charge has to be conserved - if a new negative thing exists, there has to be a new positive thing too. But the mass has to stay the same too - conveniently, protons and neutrons have almost the same mass.
During electron capture, an electron and proton combine and are converted to a neutron.
The electron is the sub-atomic particle that orbits the nucleus of an atom of matter. For anti-matter the sub-atomic particle that orbits the nucleus is the anti-electron (positron).