Radioactivity: Stability of Nucleus

Stability of nucleus is defined as – if it cannot be converted into a different structure without the addition of external energy. Only roughly 250 nuclides are stable out of thousands. The stable isotopes fall into a tight band when the number of neutrons vs the number of protons is shown. The belt of stability refers to this region. In simple words, the term stability of the nucleus refers to a notion that aids in determining an isotope’s stability. The neutron-to-proton ratio must be determined in order to determine an isotope’s stability.

Key Concept of Nucleus

Protons and neutrons make up an atomic nucleus, together known as nucleons. Although protons resist each other, the nucleus is kept together by the strong nuclear force, a short-range but extremely powerful force. The overall mass of a nucleus’ component nucleons is smaller than that of the nucleus itself.

Stability of Nucleus

The amount and ratio of protons and neutrons, which can represent closed and full quantum shells, determine the stability of an atom. The stability of an atom is determined by the ratio of protons to neutrons and the presence of a “magic number” of neutrons or protons that constitute closed and full quantum shells. The nucleus’s shell model’s energy levels correspond to these quantum shells.

A radionuclide is an atom with an unstable nucleus that has extra energy that may be used to make a new radiation particle or converted internally. The radionuclide undergoes radioactive decay during this procedure. As seen in, radioactive decay produces gamma rays and/or subatomic particles like alpha and beta particles. These sources emit ionising radiation. Radionuclides can be found in nature, but they can also be synthesised.

All elements produce radionuclides, albeit many of them have such short half-lives that they are seldom seen in nature. Tritium is a well-known radioisotope of hydrogen, the lightest element. Only radionuclides exist in the heavy elements (those heavier than bismuth).

Stable and Unstable Nucleus

• The balance of protons and neutrons determines a nucleus’s stability or instability
• The nucleus can become unstable if too many neutrons or protons are in the nucleus
• With fewer proton elements like those towards the top of the periodic table, they have the same amount of neutrons and protons
• They are stable

Stability of Nucleus Results in Radioactive Decay

As neutrons attract each other and protons, the nucleus is stabilised. This helps to balance the electrical repulsion between protons. As a result, an increasing ratio of neutrons to protons is required to build a stable nucleus as the number of protons grows. The resultant nucleus is unstable and undergoes radioactive disintegration if there are too many or too few neutrons for a given amount of protons.

Unstable isotopes decay in a variety of ways, the most frequent of which are alpha decay, beta decay, and electron capture. Other uncommon kinds of decay are known, such as spontaneous fission and neutron emission. It is important to note that all of these decay processes may result in the production of gamma radiation as a result. 

Relationship between Radioactive Disintegration and Stability of Nucleus

The unstable nucleus will spontaneously decay to generate a new nucleus in an attempt to obtain neutrons and protons’ stable arrangement. If the number of neutrons in the process changes, a new isotope is generated, and the element is preserved.

An unstable nucleus decomposes spontaneously and randomly to generate a new nucleus during radioactive decay, emitting radiation in the form of atomic fragments or high-energy rays. The half-life is the pace at which this degradation happens at a steady, predictable rate. This type of decay does not occur in a stable nucleus, making it radioactive.

Stability of Nucleus in Isotopes

The discovery of isotopes was based on two separate lines of inquiry, the first of which was the study of radioactivity. By 1910, it was evident that some radioactive processes, discovered a few years previously by French physicist Henri Becquerel, could change one element into another.

When left alone, isotopes are considered to be stable if they exhibit no discernible propensity to alter spontaneously. Even stable isotopes can be changed into one another under the right conditions, such as in a nuclear reactor or particle accelerator or in the interior of a star.

The mass of measured isotopes is compared to the masses of their component electrons, protons, and neutrons to provide a consistent scale of nuclear stability that may be used for both stable and unstable isotopes. Hydrogen atoms are formed by pairing electrons and protons for this function. The total of the individual particle masses of all stable isotopes varied significantly.

Conclusion

Outside the band of stability, nuclei are unstable and show radioactivity: they transform spontaneously or decay into nuclei that are either in or closer to the band of stability. These nuclear decay processes transform one radionuclide into a more stable nucleus.