Natural and Synthetic Radioisotopes

Vocabulary flashcards covering key terms, definitions, and concepts from the notes on natural and synthetic radioisotopes, their decay, and medical/industrial uses.

Radioisotope

Atoms that contain an unstable nucleus and undergo radioactive decay, emitting radiation (alpha, beta, or gamma rays).

Half-life

The time required for half of a given quantity of a radioactive substance to decay; describes the rate of radioactive decay.

Isotope

From Greek isos (‘the same’) and topos (‘place’); atoms of the same element with different numbers of neutrons.

Cosmic radiation

Continuously replenishes carbon-14 in the atmosphere.

Carbon-14

Emits beta particles; half-life of about 5,730 years.

Uranium-238

Emits alpha particles; half-life of approximately 4.5 billion years.

Uranium-235

Emits alpha particles; half-life of approximately 703.8 million years.

Carbon dating

A method for determining the age of organic material based on the amount of carbon-14 in a sample.

Potassium-40

Emits beta and gamma radiation; half-life of approximately 1.25 billion years.

Radium-226

Emits alpha particles; half-life of approximately 1,600 years.

Radioactive iodine therapy

Radioactive iodine ingested to target the thyroid; concentrates in the thyroid and destroys cancerous and normal thyroid cells with minimal effect on other parts.

Technetium-99m

Emits gamma radiation; half-life of 6.01 hours; used in medical imaging.

Iodine-131

Emits beta and gamma radiation; half-life of 8.03 days; used to treat thyroid disorders.

Iodine-123

Emits gamma radiation; half-life of 13.22 hours; used in medical imaging.

Fluorine-18

Emits positrons; half-life of 1.83 hours; used in PET scans.

Cobalt-60

Emits gamma radiation; half-life of 5.27 years; used in cancer treatment and sterilization.

Phosphorus-32

Emits beta particles; half-life of 14.26 days; used in molecular biology and genetics research.

Yttrium-90

Emits beta particles; half-life of 64 hours; used in cancer treatment.

Molybdenum-99

Emits beta particles; half-life of 65.94 hours; used as the parent isotope to produce Technetium-99m.

Cesium-137

Emits beta and gamma radiation; half-life of 30.17 years; byproduct of nuclear fission used in cancer treatment, industrial gauges, and detector calibration; highly radioactive.

Americium-241

Used in smoke detectors.

Iridium-192

Used in industrial radiography to check welding and metal structures.

Nuclear energy and radioisotopes

Nuclear energy usually comes from radioisotopes—radioactive isotopes.

Radioactive decay

A process by which unstable atomic nuclei lose energy and stability by emitting radiation.

Alpha particles

High-energy helium nuclei; stopped by paper or skin; harmful if ingested or inhaled.

Beta particles

High-energy electrons; stopped by thin layers of metal or plastic; can cause burns and damage if ingested or inhaled.

Gamma rays

High-energy electromagnetic radiation; require thick lead or concrete to stop; used in medical treatments and imaging.

Cosmic radiation (note)

Cosmic radiation replenishes C-14 in the atmosphere.