Radioactivity

Definition

Radioactivity is the spontaneous emission of particles or electromagnetic radiation from the unstable nucleus of an atom. This process results in the transformation of the original atom into a different element or a different isotope.

5 Must Know Facts For Your Next Test

1. Radioactive decay can occur in several forms, including alpha decay, beta decay, and gamma decay.
2. A radioactive isotope's stability is often quantified by its half-life, which is the time it takes for half of a sample to decay.
3. Alpha particles are helium nuclei, beta particles can be electrons or positrons, and gamma rays are high-energy photons.
4. The discovery of radioactivity was made by Henri Becquerel in 1896 while studying phosphorescent materials.
5. Radioactive isotopes have applications in medicine (such as cancer treatment), industry (such as radiography), and energy production (nuclear reactors).

Review Questions

• What is the difference between alpha, beta, and gamma radiation?
• How does the concept of half-life relate to radioactive decay?
• Name one application of radioactive isotopes in medicine.

Related terms

Alpha Decay:

A type of radioactive decay where an unstable nucleus emits an alpha particle (two protons and two neutrons) resulting in a new element with a lower atomic number.

Beta Decay:

A type of radioactive decay where a neutron transforms into a proton and an electron (beta particle) or positron is emitted from the nucleus.

Half-Life: The time required for half of the atoms in a sample of a radioactive substance to undergo decay.