13. Radioactivity

Página 61

Radioactivity is a natural or artificial phenomenon, by which some substances or chemical elements, called radioactive, are able to emit radiation, which have the property of impressing photographic plates, ionizing gases, producing fluorescence, passing through bodies opaque to light ordinary, among others. Radioactivity is an important tool for studying atomic structure.

In 1896, French physicist Antoine Henri Becquerel discovered radioactivity while working with a uranium mineral. He noticed that the mineral could produce its own light and emit rays that could penetrate solid materials. Becquerel's discovery was followed by the discoveries of Marie Curie and Pierre Curie, who isolated the elements polonium and radium.

Radioactivity is classified into three main types: alpha (α), beta (β) and gamma (γ). Alpha particles are the largest and heaviest, while beta particles are the smallest and lightest. Gamma rays are a form of electromagnetic energy, similar to visible light or X-rays, but of higher energy.

Alpha radioactivity occurs when an unstable atom emits an alpha particle, which is made up of two protons and two neutrons. This causes the atom to lose two protons and two neutrons, resulting in a new element. For example, when a uranium-238 atom decays, it emits an alpha particle and turns into thorium-234.

Beta radioactivity occurs when an unstable atom emits a beta particle, which is a high-energy electron. This causes one of the atom's neutrons to turn into a proton, resulting in a new element. For example, when a carbon-14 atom decays, it emits a beta particle and turns into nitrogen-14.

Gamma radioactivity occurs when an unstable atom emits gamma radiation, which is high-frequency electromagnetic energy. Gamma emission usually occurs along with alpha or beta emission, as the resulting atom is usually still in an excited state and needs to release additional energy to reach a more stable state.

Radioactivity has many practical applications. In medicine, it is used in radiotherapy to treat cancer and in nuclear medicine for diagnosis and treatment. In industry, it is used in level and thickness gauges, in industrial radiography for inspection of welds, and in nuclear power generation. In science, it is used in radiometric dating to determine the age of rocks and fossils.

On the other hand, radioactivity can also be dangerous. Exposure to ionizing radiation can cause DNA damage, leading to genetic mutations and cancer. In addition, radioactive waste produced by the nuclear industry needs to be handled and stored with care to avoid contaminating the environment.

In summary, radioactivity is a fascinating phenomenon that has many useful applications, but also requires care and caution due to its potential dangers. Understanding radioactivity and its properties is fundamental to chemistry and many other areas of science and technology.

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