Anti-particles
- Every particle has its own antiparticle.
- Antiparticles have the same mass but opposite charge to their particle counterparts.
  For example,
  - The electron’s antiparticle is the antielectron or positron.
  - The proton’s antiparticle is the antiproton.
When an antiparticle and its particle counterpart collide, annihilation takes place, releasing a significant amount of energy.
Radioactive decay is the natural process by which an unstable nucleus becomes stable by emitting particles and/or electromagnetic radiation.
Alpha particles are composed of two protons and two neutrons, which have a mass of 4 atomic mass units (u) and a charge of +2e.

When an unstable nucleus decays byemitting alpha particles, its nucleon number decreases by 4 and proton number decreases by 2.
A neutrino is a chargeless fundamental particle with very less mass. The antineutrino is the antiparticle of the neutrino.
There are two types of beta decay:
- Beta minus decay
  - It is the release of electrons from unstable nuclei.
  - They are released when a neutron converts into a proton inside the nucleus.
  - During this decay, the proton number increases by 1 whereas the nucleon number remains unchanged.
  - An antineutrino is produced during beta minus decay.
- Beta plus decay
  - It is the release of the positron from unstable nuclei.
  - They are released when a proton converts into a neutron inside the nucleus.
  - During this decay, the proton number decreases by 1, whereas the nucleon number remains unchanged.
  - A neutrino is produced during beta plus decay.
During beta decay, the energy is shared between beta particles and the neutrino, which infers emitted beta particles have a range of energy.

Gamma particle or γ-ray decay is the release of electromagnetic radiation from unstable nuclei. During γ-ray decay, the proton number and the nucleon number of unstable nuclei both remain unchanged.
All the different particles have different speed, penetration power and ionization power as shown below:
α- particles and β-particles are deflected in electric and magnetic fields, whereas γ-particles are unaffected by both the electric and magnetic fields.

11.02 - Radioactive Decay

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