WHAT IS A NUCLEAR CHANGE? - SCIENCE - 2025

A nuclear change is the process by which the nuclei of certain isotopes change spontaneously or are forced to change to two or more different isotopes.

The three main types of nuclear change in matter are natural radioactive decay, nuclear fission, and nuclear fusion.

Besides nuclear, the other two changes in matter are physical and chemical. The first does not imply any change in its chemical composition. If you cut a piece of aluminum foil, it is still aluminum foil.

When a chemical change occurs, the chemical composition of the substances involved also changes. For example, burning coal combines with oxygen, forming carbon dioxide (CO2).

Nuclear change and its main types

Radioactive natural decay

When a radioisotope emits alpha or beta particles, there is a transmutation of an element, that is, a change from one element to another.

Thus the resulting isotope has a different number of protons than the original isotope. Then a nuclear change occurs. The original substance (isotope) has been destroyed, forming a new substance (isotope).

In this sense, natural radioactive isotopes have been present since the formation of the Earth and are continuously produced by nuclear reactions of cosmic rays with atoms in the atmosphere. These nuclear reactions give rise to the elements of the universe.

These types of reactions produce stable, radioactive isotopes, many of which have a half-life of several billion years.

However, these radioactive isotopes cannot be formed under natural conditions characteristic of planet Earth.

As a result of radioactive decay, its quantity and radioactivity have gradually decreased. However, due to these long half-lives, its radioactivity has been significant so far.

Nuclear change by fission

The central nucleus of an atom contains protons and neutrons. In fission, this nucleus divides, either by radioactive decay or because it is bombarded by other subatomic particles known as neutrinos.

The resulting pieces have less combined mass than the original core. This lost mass is converted into nuclear energy.

In this way, nuclear power plants perform controlled reactions to release energy. Controlled fission occurs when a very light neutrino bombards the nucleus of an atom.

This breaks, creating two smaller, similarly sized nuclei. The destruction releases a significant amount of energy - up to 200 times that of the neutron that started the procedure.

In itself, this kind of nuclear change has great potential as a source of energy. However, it is a source of multiple concerns, especially those related to safety and the environment.

Nuclear change by fusion

Fusion is the process by which the Sun and other stars generate light and heat. In this nuclear process, energy is produced by the breakdown of atoms of light. It is the opposite reaction to fission, where heavy isotopes divide.

On Earth, nuclear fusion is easier to achieve by combining two hydrogen isotopes: deuterium and tritium.

Hydrogen, made up of a single proton and an electron, is the lightest of all elements. Deuterium, often called "heavy water," has an extra neutron in its core.

For its part, tritium has two additional neutrons and, therefore, is three times heavier than hydrogen.

Fortunately, deuterium is found in seawater. This means that there will be fuel for fusion as long as there is water on the planet.

References

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