Radioactivity and Radioactive Decay

We know that certain materials are radioactive and these radioactive materials are used in nuclear reactors. These materials are considered radioactive because they are capable of emitting energy and subatomic particles spontaneously.

The process of radioactivity was discovered by Henri Becquerel in the year 1896. Henry Becquerel was a well-known French physicist, who won the Nobel prize in 1903. The SI unit of radioactivity is the Becquerel (Bq) and is named after Henry Becquerel.

Radioactivity is one of the spontaneous discoveries. The discovery took place over several years beginning with the discovery of X-rays. Radioactivity is the process by which an unstable atomic nucleus loses energy by radiation.

When the presence of an unstable nucleus in the element is seen, the particles cannot be bound together and hence no energy is present. Radioactive decay is a property seen in naturally occurring as well as artificially produced isotopes of the elements. In this article, let us know in detail about radioactive decay.

What is Radioactive Decay?

The process of radioactive decay is also known as nuclear decay, nuclear disintegration, and radioactive disintegration. In the process of radioactive decay, a radioisotope is transformed into another radioisotope along with the emission of radiation. Radioactive decay is the process in which a nucleus loses energy by emitting radiation. Transmutation is the process in which the isotope transforms into an element of a stable nucleus.

There are three types of radioactive decay seen, they are:

  1. Alpha decay
  2. Beta-decay
  3. Gamma decay

Let us know more about what is meant by Alpha decay, Beta decay, and Gamma decay.

Alpha Decay

Ernest Rutherford, a well-known physicist distinguished alpha decay from other forms of radiation. In alpha decay, the emission of an atomic nucleus by an alpha particle takes place. Alpha particles have a relatively large mass and a positive charge. In alpha decay, the atomic mass number of the newly formed atom will be reduced by four and the atomic number will be reduced by two. The alpha particle which is emitted in this process is called a helium nucleus. 

After knowing about alpha decay, let’s now learn about the other two types of radioactive decay – beta decay and gamma decay. 

Beta Decay

In this type of decay, the emission of beta particles from an atomic nucleus is seen. The original nuclide is transformed into an isobar of that nuclide. Beta particle refers to the electron or a positron.

Beta-decay takes place in the following ways: 

  1. a) When the nucleus emits an electron and an antineutrino, where a neutron changes into a proton.
  2. b) When the nucleus emits a positron and a neutrino, where a proton changes into a neutron.

Gamma Decay

In this type of radioactive decay, the emission of electromagnetic radiation of an extremely high frequency is seen. There is the production of excess energy to stabilize the unstable nucleus. In gamma decay, the nucleus drops from a higher energy level to a lower energy level through the emission of high-energy photons.