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Nuclear stability refers to the tendency of a nucleus of an atom to decay, which means to change into something else. If the isotope of an element (called a nuclide) is unstable (not stable), the nuclide has the tendency of emitting some kind of radiation, and is called radioactive. Radioactivity is associated with unstable nuclides.
The Chart of the Nuclides, part of which is shown in Fig. 3-1, is a plot of nuclei as a function of proton number, Z, and neutron number, N. All stable nuclei and known radioactive nuclei, both naturally occurring and manmade, are shown on this chart, along with their decay properties.
This nuclear stability curve shows the line of stable isotopes and which unstable isotopes will emit alpha or beta particles. A nucleus will be unstable if it has: Too many neutrons. Too many protons. Too many nucleons ie. too heavy. Too much energy. For light isotopes, Z < 20: All these nuclei tend to be very stable.
The nuclear stability curve depicts the binding energy per nucleon as a function of the mass number (A) of atomic nuclei. The curve shows that nuclei with intermediate mass numbers, around A = 56 for iron, have the highest binding energy per nucleon, indicating the greatest stability.
Nuclear stability rules. Notation: N = number of neutrons = A Z For small Z (< 20), N Z for stable nuclei. Example: Carbon has two stable isotopes, 12 6C (98.9%) and 13 6C (1.1%). For larger Z, N > Z, with the N=Z ratio rising slowly from 1 to 1.54 as Z increases from 20 to 82.
Nuclear Stability Stable nuclei only occur in a very narrow band in the Z N plane (Fig.3.1). All other nuclei are unstable and decay spontaneously in various ways. Isobars with a large surplus of neutrons gain energy by converting a neutron into a proton. In the
29 Ιουλ 2023 · All the stable nuclei lie within a definite area called the zone of stability. For low atomic numbers most stable nuclei have a neutron/proton ratio which is very close to 1. As the atomic number increases, the zone of stability corresponds to a gradually increasing neutron/proton ratio.
