The excess energy associated with this excited state is released when the nucleus emits a photon in the -ray portion of the electromagnetic spectrum.Most of the time, the -ray is emitted within 10Nuclides with atomic numbers of 90 or more undergo a form of radioactive decay known as spontaneous fission in which the parent nucleus splits into a pair of smaller nuclei.
In 1934 Enrico Fermi proposed a theory that explained the three forms of beta decay.Alpha decay is usually restricted to the heavier elements in the periodic table.(Only a handful of nuclides with atomic numbers less than 83 emit an -particle.) The product of -decay is easy to predict if we assume that both mass and charge are conserved in nuclear reactions.Alpha decay of the The sum of the mass numbers of the products (234 + 4) is equal to the mass number of the parent nuclide (238), and the sum of the charges on the products (90 + 2) is equal to the charge on the parent nuclide.Nuclei can also decay by capturing one of the electrons that surround the nucleus.Electron capture leads to a decrease of one in the charge on the nucleus.
The energy given off in this reaction is carried by an x-ray photon, which is represented by the symbol hv, where h is Planck's constant and v is the frequency of the x-ray.
The product of this reaction can be predicted, once again, by assuming that mass and charge are conserved. They rapidly lose their kinetic energy as they pass through matter.
As soon as they come to rest, they combine with an electron to form two -ray photons in a matter-antimatter annihilation reaction.-decay are often obtained in an excited state.
He argued that a neutron could decay to form a proton by emitting an electron.
A proton, on the other hand, could be transformed into a neutron by two pathways.
It can capture an electron or it can emit a positron.