Radioactive Emissions

Radioactive Emissions

General Overview

• Radioactive emissions are particles or energy released from unstable nuclei of certain atoms.
• This process of atom’s nucleus breaking down and emitting radiation in order to become stable is known as radioactive decay.
• The three main types of radioactive emissions are alpha particles, beta particles, and gamma rays.

Alpha Particles

• Alpha (α) particles consist of two protons and two neutrons, identical to the nucleus of a helium atom.
• They are the most heavily charged but the least penetrating of the three main types. They can be stopped by a sheet of paper or a few centimetres of air.
• When an atom emits an alpha particle, its nucleon number decreases by 4 and its proton number decreases by 2.

Beta Particles

• Beta (β) particles are high-energy electrons or positrons emitted from the nucleus.
• They are more penetrating than alpha particles but less than gamma rays. They can be stopped by thin sheets of aluminium or plastics.
• Emitting a beta particle leads to the transformation of a neutron into a proton within a nucleus. There is no change in the nucleon number, but the proton number increases by 1.

Gamma Rays

• Gamma (γ) rays are electromagnetic waves emitted by the nucleus. They have no mass and no charge.
• They are the most penetrating of the three, able to pass through several centimetres of lead or several metres of concrete. Gamma rays require thick lead or concrete to be blocked efficiently.
• An atom usually emits gamma rays following the emission of alpha or beta particles when the remaining nucleus drops to a lower energy state.

Hazard and Safety Measures

• Exposure to radioactive emissions can be harmful. It is necessary to take safety measures like maintaining distance from the source, using shielding, or limiting the exposure time.
• The effect of exposure can vary significantly depending on the type of radiation, so a proper understanding of different types of emissions is paramount.

Radioactive Decay

• Radioactive decay is a random process. It is impossible to predict when a specific nucleus will decay, but with large numbers of nuclei, the average decay rate can be predicted with a good degree of accuracy.
• The rate of decay is expressed through half-life, the time required for half the radioactive atoms in a sample to decay.

There is a lot to remember about radioactive emissions, but it’s key to grasp the differences between alpha, beta, and gamma particles in terms of their composition, penetration level, and what changes they cause to the atom’s nucleus.