Radioactivity and Ionizing Radiation

These flashcards cover key vocabulary and concepts related to radioactivity and ionizing radiation, including definitions of various types of radiation and nuclear reactions.

Radioactivity

The spontaneous emission of radiation from a nucleus.

Alpha Particle

A helium nucleus (4 2He) that moves slowly and can be stopped by a few sheets of paper.

Beta Particle

An electron (0 -1e) that moves close to the speed of light and has about 100 times the penetrating power of alpha particles.

Gamma Radiation

High-energy electromagnetic waves that have no mass and require a lead block to stop.

Radioisotope

A radioactive isotope.

Radionuclide

The nucleus of a radioisotope.

Nuclear Decay

The spontaneous emission of a particle from an unstable nucleus.

Transmutation

The change of one element to another.

Half-life (t1/2)

The amount of time required for one-half of a radioactive sample to decay.

Alpha Emission

The release of alpha particles (helium nuclei) from the nuclide.

Beta Emission

The decomposition of a neutron to yield an electron and a proton.

Gamma Emission

The release of high-energy gamma rays from the nuclide.

Positron Emission

The conversion of a proton in the nucleus into a neutron plus an ejected positron.

Electron Capture

A process in which the nucleus captures an inner-shell electron from the surrounding electron cloud.

Stability of Isotopes

In the first few rows of the periodic table, stability is associated with a roughly equal number of neutrons and protons.

Radioactivity and Stability

All isotopes with Z ≥ 84 are radioactive.