hello puja rani,

Radioactive decay occurs in unstable atomic nuclei, that is, those that do not have enough binding energy to keep the nucleus together due to an excess of protons or neutrons. Radioactivity can be natural or artificial. In natural radioactivity, the substance already has it in the natural state.

Radioactivity is caused when an atom, for whatever reason, wants to give away some of its energy. It does this because it wants to shift from an unstable configuration to a more stable configuration. The energy that is released when the atom makes this shift is known as radioactivity.

Radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold the nucleus together due to an excess of either protons or neutrons. It comes in three main types – named alpha, beta and gamma for the first three letters of the Greek alphabet.

There are three primary types of radiation:

• Alpha - these are fast moving helium atoms. ...
• Beta - these are fast moving electrons. ...
• Gamma - these are photons, just like light, except of much higher energy, typically from several keV to several MeV

Altogether, there are three major types of nuclear decay that radioactive particles can undergo: alpha, beta, or gamma decay. Each type emits a particle from the nucleus.

Alpha particles are high-energy helium nuclei containing 2 protons and 2 neutrons.

beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar.

In the most common form of gamma decay, known as gamma emission, gamma rays (photons, or packets of electromagnetic energy, of extremely short wavelength) are radiated.

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