What is Radioactivity? Explained

What is Radioactivity


In nature, there are some atoms whose nucleus is in an unstable state. For this instability, atoms emit some ionizing radiation or particles from the nucleus and try to be stable. This phenomenon of particle emission from the nucleus of atoms is known as radioactivity.

If you do not know what is radioactivity, this article is for you. Today, I am going to unlock the details of the radioactivity. In this article, you will know -

1. What is Radioactivity?
2. Why Radioactivity occur?
a) Radioactive substances
b) Radioactive isotopes
c) Nature of radioactivity
3. Discovery of Radioactivity
4. Use of radioactivity

What is Radioactivity?

Radioactivity is a nuclear phenomenon. It is the process of spontaneous emission of Alpha(𝛼), Beta(𝛽), and Gamma(𝛾) radiations from the nuclei of atoms during their decay. In this process, an unstable atomic nucleus breaks into the smaller atomic nucleus and try to be as steady as possible.

The original nucleus is called the parent nuclei, while the resulting nuclei are called the daughter nuclei. The resulting daughter nuclei might still be radioactive, eventually breaking into more parts, or they might be stable.

Why Radioactivity occur?

We all know that atoms are made up of three subatomic particles called electrons, protons, and neutrons. Where the center of the atom called the nucleus is composed of protons and neutrons. If we talk about the charge of these particles, then the electron has negatively charged, proton has positively charged and neutron has no charge i.e neutral.

The ratio of the proton-to-electron is always one to one, so the atom as a whole has a neutral charge. For example, a carbon atom has 6 protons and 6 electrons. The properties of an atom can change considerably, depending on how many of each particle it has.

The changes in the number of neutrons in the nucleus of an atom produce different isotopes of that atom. For example - carbon has three isotopes:

1) carbon-12 (has six protons and six neutrons in its nucleus), It is a stable and commonly occurring form of the element.
2) carbon-13 (has six protons and seven neutrons in its nucleus), It is stable but rare.
3) carbon-14 (It has six protons and eight neutrons in its nucleus), It is unstable (i.e radioactive isotope) and rare.

As we can see with carbon, most atomic nuclei are stable, but some are not stable. If there are too many neutrons compared to protons, the nucleus becomes unstable. For this instability, the nuclei try to stabilize by releasing nuclear radiation in the form of alpha particles, beta particles, and gamma radiation.

The process of emitting these particles is known as radioactive decay. And scientists refer to the spontaneous emission of these particles as radiation.

Radioactive substances:

The substances which decay (or disintegrate) by the spontaneous emission of radiations are called radioactive substances. Example - Some of the radioactive substances are Uranium (U), Radium (Ra), Thorium (Th), Polonium (Po), and Actinium (Ac).

Radioactive isotopes:

The isotopes which decay (or disintegrate) by the spontaneous emission of radiations are called radioactive isotopes or radioisotopes. Example - Some of the radioactive isotopes are Uranium-238 (The best-known example of a naturally-occurring radioisotope), Uranium-235, Molybdenum-99, Fluorine-18, etc.

Nature of radioactivity:

Radioactivity is a nuclear phenomenon. Any physical changes (such as pressure and temperature) or any chemical changes (such as excessive heating, freezing, actions of strong electric and magnetic field, chemical treatment, oxidation, etc) can not change the rate of decay.

So it is clearly understandable that the radioactive phenomenon can not be due to the orbital electron which could easily be affected by such changes.

Discovery of Radioactivity

In the year 1896, the French physicist Henri Becquerel studied the properties of x-rays. He was using naturally fluorescence and phosphorescence minerals to study the properties of x-rays, which Wilhelm Rontzen discovered in 1895.

Becquerel found that, while fluorescence and phosphorescence have many similarities with each other and x-rays, but there were also significant differences.

He connects energy sources to produce x-rays. When the initiating energy source was switched off then fluorescence and x-rays stopped, but phosphorescence continued to emit rays sometime after the initiating energy source was removed. However, in all three cases, the energy was initially obtained from the external source.

Becquerel exposed the potassium uranyl sulfate to sunlight and then placed it on a photographic plate wrapped in black paper, believing that uranium absorbs the sun's energy and then emitted as an x-ray.

But his test failed because that day the sky was cloudy. So he left his wrap photographic plates in a dark drawer, as well as some uranium-containing crystals.

Becquerel was surprised that the plates were exposed during storage by invisible emissions from the uranium. This emission did not require the presence of an initiating energy source. The crystals emitted rays on their own. What Becquerel had discovered was radioactivity.

After that, In 1898, Marie Curie and her husband Pierre Curie discovered the strongly radioactive elements polonium and radium, which occur naturally in uranium minerals. Their work on radioactivity began, which has now become a lifelong study of radioactivity.

Use of radioactivity

1. The Radioactivity tracers are commonly used in the medical field and also in the study of plants and animals.

2. Radiations are used and produced in nuclear reactors, which controls fission reactions to produce energy and new substances from the fission products.

3. Radiations are also used to sterilize medical instruments and food.

4. Radiations are used by test personnel who monitor materials and processes by nondestructive methods such as x-rays.

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