Example of Radioactive Elements

The word radioactive refers to a chemical element whose atom is unstable and for that reason it continuously emits radiation, which would bring it directly to a state of energy stability, or another of instability in which the radiation would continue to be released to the outside continuously.

Radiation emissions imply the detachment of subatomic particles, so the atom of a chemical element that has already made repeated emissions is going to transform into the atom of another smaller chemical element. The radioactive nature of some substances has led to extensive research and the development of useful applications for humans.

Discovery of radioactive elements

In 1895, Henry becquerel was inspired by Roentgen's discovery of X-rays to study whether the fluorescence emitted by uranium salts was similar to X-rays. After experimenting with photographic plates isolated from sunlight, he discovered that uranium salts left an impression with their exact shape on the plates.

That print with the shape of uranium salts 

he had nothing to do with her fluorescence, because this only appeared when there was light. It was, then, a form of energy that collided with the plates, leaving that trace even in the dark. Henry Becquerel named this energy as Becquerel rays.

It was in 1896 that Marie Curie began her exhaustive work to investigate the nature of Becquerel rays. It was in 1898 that he communicated his results and showed that there were substances such as Thorium and its compounds, which had effects such as ionizing the air and altering photographic plates.

Furthermore, she discovered that the mineral pitchblende it had an activity of three to four times greater than that of the present uranium, reason why it suspected that a new substance could be in this mineral. Her husband Pierre partnered with her in the research, and after isolating this element, they discovered that this was the case until 400 times more active than uranium. They call him Polonium.

Upon further investigation of him with the mineral pitchblende, they continued to precipitate in alcohol and in aqueous solution a fraction of barium that emitted active radiation, which resulted 900 times greater than pure uranium. They belonged to another new element, which they called Radio.

In the radiation emitted by the Radio they observed impressive properties:

• Transform oxygen (O₂) in ozone (O₃).
• Hydrogen peroxide (H₂OR₂).
• The radiations emitted destroy living cells. This property has made this element valuable in the treatment of cancer.
• Ferric salts (Fe⁺³) and mercuric (Hg⁺²) are reduced to ferrous (Fe⁺²) and mercury (Hg⁺¹).

Radiations emitted by radioactive elements

The scientist Ernest Rutherford was in charge of studying the radiation of the elements radioactive, and classified them into three groups, according to their behavior in an electric field or magnetic:

• Alpha rays or particles
• Beta rays or particles
• Gamma rays or particles

The rays or alpha particles have a positive charge, and are nuclei of the element Helium (He). They deviate slightly toward the negative pole (opposite of the positive) in an electric field and similarly in a magnetic field. They are expelled from the nucleus of the radioactive element at a speed of 2 * 10⁷m / s.

The beta rays or particles have a negative charge and are electrons emitted by the atoms of some elements at speeds close to that of light (3 * 10⁸ m / s). The speed of beta particles is greater than that of alpha particles, because an electron has a mass much smaller than helium nuclei.

The gamma rays They have no charge, so they are not deflected in an electric or magnetic field. It has been assumed from this that they do not consist of particles, but of electromagnetic waves. They are more penetrating than X-rays. It follows then that their wavelength is shorter than that of these, and that therefore they are more powerful rays.

Uses of radioactive elements

Emissions are exploited from radioactive elements, since they have useful properties for various industrial and research purposes. Its applications include:

• The Carbon-14 it is a protagonist in the area of ​​archeology, since it allows us to measure the age of fossils and of all kinds of remains of natural origin.
• The Uranium-238 and the Plutonium They are the main materials used to obtain nuclear energy. Its radioactive decay emits a large amount of energy that can be transformed into electricity to support the needs of the population. It is the best option as non-polluting energy; however, it is dangerous if there is a failure in the nuclear plant.
• The Radio it is the element whose radiation kills cancer cells during chemotherapy. It has proven effective for these treatments.

Examples of radioactive elements

• Uranium-238 (U)
• Uranium-239 (U)
• Plutonium (Pu)
• Polonium (Po)
• Radius (Ra)
• Thorium (Th)
• Radon (Rn)
• Protactinium (Pa)
• Carbon-14 (C)
• Iodine-131
• Hydrogen-3 (Tritium)