Question

What is meant by radioactivity?
We know that, in chemical reactions, atoms can lose, gain or share valence electrons but identification of atoms does not change. But nuclear reactions are those reactions in which combination, splitting of nuclei and emission of radiation takes place.

Answer 1

Let’s discuss radioactivity in detail. Radioactivity is the property of atomic nuclei to emit radiation spontaneously. Those elements capable of emitting radiation are termed as radioactive substances.

Complete step by step answer:
Now, we discuss the types of radiation. Three most common types of radiation are alpha $\left( \alpha \right)$, beta $\left( \beta \right)$ and gamma $\left( \gamma \right)$
- Alpha radiation is the radiation in which an alpha particle is emitted by an unstable nucleus and the process transforms the atom into a stable atom. Alpha particles possess the same composition as helium atoms (two protons and two neutrons) and symbol is ${}_2^4{\rm{He}}$. One example of alpha decay is decay of uranium.
${}_{92}^{238}{\rm{U}} \to {}_{90}^{234}{\rm{Th + }}{}_2^4{\rm{He}}$
The decay of uranium emits an alpha particle and uranium transforms to thorium.
-Beta radiation is the radiation in which a beta particle emitted when a neutron in unstable nuclei converts into a proton. One example of beta radiation is decay of iodine -131.
${}_{53}^{131}{\rm{I}} \to {}_{54}^{131}{\rm{Xe}} + \beta$
In the decay of iodine-131, one neutron converts to proton and thus atomic number increases by one and a beta particle releases.
-Gamma radiation is the radiation in which emission of gamma rays takes place. Gamma rays are photons of high energy electromagnetic radiations. As photons have no charge and mass, its emission does not change the atomic number or mass number of the element.
${}_{92}^{235}{\rm{U}} \to \gamma + {}_{92}^{235}{\rm{U}}$

Note: There are many uses of radioactivity such as it is used to check the working of organs in the human body and sterilization of medical equipment and food. It also kills cancer cells and is used in the smoke detection process.