Radioactivity is defined as a phenomenon where an element emits radiation due to the unstable nucleus.

Radioactivity is a phenomenon where an element with the nucleus is unstable as the Coulomb force between the protons and the attractive force between the neutrons are not in equilibrium. On the basis of radiation or decay, radioactivity is categorised into three groups, alpha decay, beta decay and gamma decay. Radioactivity has been used in various medical fields, geological fields, etc. On the other hand, radioactive elements are quite severe when they come to human contact. The radioactivity is measured by a standard unit, which is termed as Becquerel, denoted by Bq, which is named after a scientist Henry Becquerel. Plutonium and Uranium are some of the most radioactive elements present.


Radioactivity definition explains this phenomenon as the emission of radiation from several radioactive elements. These radiations are in the form of high energy photons or particles, which are caused by nuclear reactions. Radioactivity is also termed radioactive decay, nuclear decay of radioactive disintegration. Radioactivity occurs in those elements that have an unstable atomic structure, i.e., unstable proton and neutron bonds. The SI unit of radioactivity is Becquerel. During the emission of these radioactive radiations, there are three variations of particles that are emitted, alpha particle, beta particle and gamma particle.


Radioactivity is a phenomenon of the emission of radiation from an unstable atomic nucleus of an atom material or element or metal. These radiations are categorised into three groups on the basis of their penetration capability. The three types of radioactive decay are :-

Alpha Decay: Alpha decay radiates from the particles, which are basically made up of two protons or two neutrons. Ideally, these are identical to the helium atom. These particles are heavy in nature, and they radiate at a slow pace. Due to having a slow speed, the alpha particles have a weak penetration power. However, these particles are highly ionising.

Beta Decay: Beta decay emits beta particles that are fast-moving electrons compared to alpha particles. These are lightweight and are negatively charged. It has great penetration power. As these particles are negatively charged, they are attracted towards positively charged particles.

Gamma Decay: Gamma rays are the highest energy influenced particles. These are emitted from the radioactive elements, and these have the most energetic photons in comparison to Alpha and Beta particles. It has high penetration power as well as the wavelength is the shortest among all the particles.


Radioactivity definition expresses it as a phenomenon where an element emits radiation due to atomic instability. This radiation is emitted from the nucleus of that atom, and the nucleus is said to be a combination of neutrons and protons. The force between protons is known as the Coulomb force, whereas there is a strong, attractive force between the nucleons. If the balance in the nucleus is not balanced, it results in the emission of radiation. The assumption is made that if a nucleus consists of an odd number of protons or an odd number of neutrons, there are high chances of it being radioactive. Therefore, the nucleus of an element is the root cause of radioactive emission.


The measuring unit of radioactivity is Becquerel, which is named after the scientist Henry Becquerel. It is denoted as Bq. There are other units of measurement, like, Curie, that is denoted by Ci, which used to be the original unit for radioactivity. Its value is equal :

Radioactivity is measured on the basis of the ionising radiation which is released from that radioactive element.


Radioactivity is a natural phenomenon that can be seen in our daily life. There are several examples of radioactive radiation in the medical field, like it is used for scanning the internal parts of the bodies, the gamma rays are quite effective in killing the cancer cells, etc. Radioactivity is also used in the geological field, where fossil fuels and carbon dating are being done. The radioactive elements are used for smoke detecting machines. Whereas the radioactive elements could be quite dangerous for human health, and high exposure to radioactive radiation can cause death. There have been disasters regarding radioactivity, for example, The Chernobyl tragedy


Radioactivity is termed as the emission of radiation from an element whose nucleus is not in equilibrium. The nucleus is composed of neutrons and protons, which are bounded by force. The proton is considered to have a Coulomb force, whereas neutrons have a strong, attractive force. Whenever these forces lose stability, they become an unstable nucleus, emitting radiation. Some of the elements are highly radioactive, and some do not possess radioactivity. On the basis of this radiation emission, radioactivity is divided into three types, alpha, beta and gamma radiations. Radioactivity has been proved very beneficial in this modern science as well, as there are several drawbacks. To know more about radioactivity is required to acquire knowledge of the concept of Carbon dating and Half-life.