Giving off, or capable of giving off, radiant energy in the form of particles (alpha or beta radiation) or rays (gamma radiation) by the spontaneous disintegration of the nuclei of atoms Radioisotopes of elements lose particles and energy through the process of radioactive decay Elements may decay into different atoms or a different state of the same atom
Radioactive describes the spontaneous disintegration of atomic nuclei accompanied by the emission of small particles Depending on the type of emission, scientists define alpha (helium nuclei), beta (electrons or positrons), and gamma radiation (short-wavelength electromagnetic waves)
a property of certain elements, or isotopes of an element, whose atomic nuclei are unstable and subject to spontaneous disintegration, thereby giving off ionizing radiation
Giving off or capable of giving off radiant energy in the form of particles or rays, as in alpha, beta, and gamma rays
Having unstable atoms that decay or break down to another kind of atom The process emits high-energy particles For example, radium decays to form radon Radiation includes high-energy particles, which include alpha and beta particles and gamma rays
A word used to describe substances that contain atoms that emit nuclear radiation How radioactive a substance is depends on its activity
These nuclei are unstable They decay by emitting alpha or beta particles or gamma rays
exhibiting or caused by radioactivity; "radioactive isotope"; "radioactive decay"; "radioactive fallout
Describing the spontaneous breakdown of atomic nuclei (normally the heaviest atoms) into lighter nuclei with the ejection of alpha particles, electrons, and gamma photons
{s} emitting energy as a result of atomic decay, radiating energy in waves or moving particles
Property of undergoing spontaneous nuclear transformation in which nuclear particles or electromagnetic energy are emitted
An unstable isotope that decays spontaneously and releases subatomic particles or units of energy
Something that is radioactive contains a substance that produces energy in the form of powerful and harmful rays. The government has been storing radioactive waste at Fernald for 50 years. + radioactivity radio·ac·tiv·ity waste which is contaminated with low levels of radioactivity. a radioactive substance is dangerous because it contains radiation (=a form of energy that can harm living things)
a radioactive isotope which, when injected into a chemically similar substance, or artificially attached to a biological or physical system, can be traced by radiation detection devices
A group of isotopes representing various stages of radioactive decay in which the heavier members of the group are transformed into successively lighter ones, the lightest being stable. Any of four sets of unstable heavy atomic nuclei that undergo a series of alpha decay and beta decay until a stable nucleus is achieved. The natural series are the thorium series, the uranium series, and the actinium series. These are headed by naturally occurring species of unstable nuclei that have half-lives comparable to the age of the earth. The fourth set, the neptunium series, is headed by neptunium-237, which has a half-life of 2 million years. Its members do not occur naturally but are artificially produced by nuclear reactions and have short half-lives