The spontaneous decay or disintegration of unstable atomic nuclei, accompanied by the emission of radiation.

spontaneous transformation of the nucleus of an atom; this resulting in a new element, generally with the emission of alpha or beta particles often accompanied by gamma rays [] [ Click "BackButton" for previous location

The spontaneous disintegration of an unstable atomic nucleas, resulting in the emission of subatomic particles.

Radioactivity is the spontaneous emission of radiation and atomic particles from unstable elements. Radioactivity is measured in terms of half-lives and is not affected by physical state or chemical combination.

Radioactivity is the spontaneous release of radiation from the nucleus of an atom.

the emission of subatomic particles from a nucleus.

The spontaneous discharge of radiation from atomic nuclei. This is usually in the form of beta or alpha radiation, together with gamma radiation. Beta or alpha emission results in transformation of the atom into a different element, changing the atomic number by +1 or -2 respectively.

The property exhibited by certain unstable elements of spontaneously emitting mass or energy from the nucleus.

The spontaneous emission of particles and/or energy from atomic nuclei.

the process in which atoms undergo internal change with the resultant emission of electromagnetic or particulate radiation.

The emission of energetic particles and/or radiation during radioactive decay.

The spontaneous disintegration of an unstable nuclide by a first-order rate law.

The property of certain nuclides to spontaneously transform into other elements by emitting alpha or beta particles.

Radioactivity is a natural process by which the excess energy of unstable atoms is released spontaneously in the form of particles or waves. The end product of this activity is radiation.

Ability of some atoms to give off energy in the form of radiation (gamma rays) or particles (ex.: electrons).

The spontaneous disintegration of some atomic nuclei with emission of energy in the form of radiation.

The emission of particles by the decay of atoms of certain substances.

Spontaneous emission of alpha, beta, or gamma rays by the disintegration of the nuclei of atoms.

3/4 The property of certain nuclides of emitting radiation by the spontaneous transformation of their nuclei.

the process by which some nuclei spontaneously split and emit particles.

High energy particles emitted by radioactive substances.

The spontaneous release of energy from atomic nuclei.

A property of unstable isotopes. which undergo spontaneous atomic readjustment with the liberation of particles and/or energy (e.g., alpha or beta particles, neutrons, and gamma rays). Alpha and beta enmission change the chemical nature of the element involved. The loss of energy will result in the decay or transformation of the unstable isotope into a stable isotope; or transmutation into an isotope of another element, sometimes giving rise to emission of neutrons. The process of radioactive decay is one of conversion of mass to energy in accordance with Einstein's relationship, E = mc2. Nearly all of the energy of emitted particles and photons is converted to heat in the near vicinity of the radioactive parent. This is one means by which the temperature of the earth is maintained.

The effect of radioactive material, emitting alpha, beta, and gamma rays. Also used to describe in present tense the nature of radioactive material.

The spontaneous disintegration of an atomic nucleus with the emission of energy.

The property of a radionuclide to spontaneously emit ionising radiation. It arises from the breakdown of an unstable nucleus

Spontaneous decay of atomic nuclei. An unstable nucleus may decay to one or more lighter nuclei. During the process radiation is emitted. There are three types of radioactive emissions: alpha particles (nuclei of helium), beta-rays (fast electrons) and gamma rays (high-energy photons). In the Universe radioactive atoms are formed in supernova explosions.

property found in certain naturally occurring or artificial elements causing them to emit spontaneously alpha particles (helium nuclei), beta particles (positrons [beta + emission] or electrons [beta - emission]) and/or gamma radiation (high-energy photons). More generally speaking, the term refers to radiation emitted during the disintegration of an unstable element or fission

The emission of radiation from the spontaneous disintegration ( decay) of an unstable nuclide.

The release of energy by rare, heavy elements when their nuclei decay into lighter nuclei.

The decay of unstable nuclei through the emission of ionizing radiation. The resulting nucleus may itself be unstable and undergo radioactive decay. The process stops only when the decay product is stable.

the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay

the property possessed by some elements (as uranium) of spontaneously emitting alpha or beta rays and sometimes also gamma rays by the disintegration of the nuclei of atoms.

The spontaneous breakdown of one type of atomic nucleus into another.

The process by which certain kinds of atomic nuclei naturally decompose, with the spontaneous emission of subatomic particles and gamma rays.

The property of radionuclides of spontaneously emitting ionizing radiation.

the process of spontaneous transformation of the nucleus, generally with the emission of alpha or beta particles often accompanied by gamma rays. This process is referred to as decay or disintegration of an atom.

release of alpha and beta particles and gamma rays when atoms of one element change to atoms of another element

radiation emitted from atomic nuclei

It is the effect of radioactive material, which emits alpha, beta, and gamma rays.

The spontaneous decay of an atomic nucleus (especially of elements with a high number of protons in it) by emitting either electromagnetic radiation (gamma-radiation) or high energy particles (protons: alpha radiation, electrons: beta radiation).

The spontaneous decay of an unstable atom. During the decay process, ionizing radiation is usually given off.

The spontaneous disintegration of unstable atomic nuclei with the resulting emission of radiation.

The emission of alpha and beta particles and gamma rays by the atomic nuclei as they decay.

The property of a certain nuclide to spontaneously emit particles or gamma or X-radiation following a nuclear transformation.

The property or characteristic of an unstable atomic nucleus to spontaneously transform with the emission of energy in the form of radiation.

the spontaneous emission of radiation from atomic nuclei

The property of certain nuclides of spontaneously disintegrating and emitting radiation.

The spontaneous emission of radiation, generally alpha or beta particles, often accompanied by gamma rays, from the nucleus of an unstable nucleus.

A behavior of an element in which nuclei are undergoing change and emitting particles. This occurs naturally in approximately fifty elements. It can be produced artificially.

emission of ionising radiation caused by the spontaneous transformation of atomic nuclei

The process of undergoing spontaneous transformation of the nucleus, generally with the emission of alpha or beta particles, often accompanied by gamma rays. The term is also used to designate radioactive materials.

A natural and spontaneous process by which the unstable atoms of an element emit or radiate excess energy from their nuclei and, thus, change (or decay) to atoms of a different element or to a lower energy state of the same element.

The spontaneous decay of an unstable atom, usually accompanied by the emission of ionizing radiation.

the property of some elements to emit spontaneously rays of radiant energy by the decay of their atomic nuclei

Any element that exhibits spontaneous disintegration of atomic nuclei, emitting alpha-particles, beta-particles (electrons), or gamma waves (x-rays).

The property possessed by some elements which enables them to give off energy in the form of particles or waves.

The decay of unstable nuclei giving rise to radiation

Nuclear transformation, either by natural or artificial means, resulting in emission of energy in the form of alpha, beta, or gamma rays.  Amounts of radioactive material are described by the rate of radioactive decay, the Curie (Ci), or in metric multiples and fractions thereof.

A term describing a phenomenon whereby certain materials are subject to a form of decay brought about by the emission of high-energy particles or radiation. Forms of particles or energy include alpha particles (positively charged helium nuclei), beta particles (either electrons or subatomic particles called positrons, or gamma rays, which occupy the highest energy level in the electromagnetic spectrum.

Nuclear change in which unstable nuclei of atoms spontaneously shoot out "chunks" of mass, energy, or both at a fixed rate. The three principal types of radioactivity are gamma rays and fast-moving alpha particles and beta particles.

A term describing a phenomenon whereby certain isotopes known as radioisotopes are subject to a form of decay brought about by the emission of high-energy particles. "Decay" does not mean that the isotope "rots"; rather, it decays to form another isotope until eventually (though this may take a long time), it becomes stable.

A term describing a phenomenon whereby certain materials are subject to a form of decay brought about by the emission of high-energy particles. "Decay" in this sense does not mean "rot"; instead, radioactive isotopes continue to emit particles, changing into isotopes of other elements, until they becomestable.

The spontaneous decay of disintegration of an unstable atomic nucleus accompanied by the emission of radiation.

All elements (=the building stones of all chemical substances - incl. biological) have nuclei that are made from protons (carrying a positive electrical charge) and neutrons (without an electrical charge). If the balance between the number of protons and neutrons is not optimal, the nucleus will be unstable, and will try to become stable by getting rid of excess protons or neutrons, or to add either to "improve" the balance. These processes to improve the balance is accompanied by different types of high energy radiation, called alpha, beta and gamma radiation, all of which are radioactive. Radioactivity is a type of ionising radiation and occurs naturally or may be a result of a nuclear reactor process.

The spontaneous emission of radiation from the nucleus of an unstable atom. As a result of this emission, the radioactive atom is converted, or decays, into an atom of a different element that might or might not be radioactive.

the property of an element to emit energy through disintegration of the nuclei of its atoms.

radiation; radioactive. Spontaneous emission of particles or high-energy electromagnetic radiation from the nuclei of unstable atoms. "Radiation" refers to the emissions, and "radioactive source" refers to the source of the radiation.

Spontaneous decay or disintegration of unstable atomic nuclei accompanied by the emission of charged particles and gamma rays.

Instability of the nuclei of atoms, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain. The 3 "classical" types of radioactive emissions are (1) alpha particles, nuclei of helium (2) beta-rays, fast electrons and (3) gamma-rays, high-energy photons.

The property of the nuclei of certain atoms spontaneously emitting particles or gamma radiation or of emitting x radiation following orbital electron capture or of undergoing spontaneous fission. Atomic nuclei are of two types, stable and unstable. Unstable nuclei are said to be radioactive and eventually are transformed by radioactive decay into the stable nuclei. One or more of the three types of radioactive emissions ( or particles or -rays) occur during each stage of the decay.

the spontaneous releasing of energy or particles from the nuclei of some atoms.

Energy emitted as particles or rays during the decay of an unstable isotope to a stable isotope.

The spontaneous emission of radiation from the nucleus of an atom. Radioisotopes of elements lose particles and energy through the process of radioactive decay.

The spontaneous transformation of an unstable atom and often results in the emission of radiation. This process is referred to as a transformation, a decay, or a disintegration of an atom.

The spontaneous emission of radiation (alpha, beta, gamma rays, or neutrons) from an unstable nuclide.

The spontaneous decay of an unstable atomic nucleus, giving rise to the emission of radiation.

the spontaneous emission of matter or energy from the nucleus of an unstable atom (the emitted matter or energy is usually in the form of alpha or beta particles, gamma rays, or neutrons).

The property of radionuclides of spontaneously emitting ionising radiation.

The spontaneous decay of certain rare, unstable, heavy-weight nuclei into more stable light-weight nuclei, a natural by-product of which is the release of energy.

Emissions of radiant atomic energy (alpha, beta, and/or gamma rays) from some elements (radium, radon, uranium, thorium, etc.) caused by the spontaneous disintegration of the nuclei of the atoms of these elements.

The property of spontaneously emitting alpha, beta or gamma rays by the decay of the nuclei of atoms.

The process whereby isotopes of certain elements spontaneously emit particles and/or rays from radioactive materials. Any process by which unstable nuclei increase their stability by shooting out particles (alpha or beta) or gamma rays.

1. The spontaneous transition of an atomic nucleus to a lower energy state (radioactive decay) accompanied by the emission of an alpha particle beta particle, or gamma radiation. Alpha emission results in a reduction of atomic number by two and mass number by four; (negative) beta emission results in an increase of atomic number by one but no change in mass number; in gamma emission, atomic number and mass number are unchanged. Several naturally occurring isotopes are radioactive, including carbon-14 and potassium-40, which reside in the human body. Radon (strictly, radon-222) is a natural radioactive gas originating ultimately from the radioactive decay of uranium-238. Artificial radioactivity, as opposed to natural radioactivity, is a consequence of bombardment of isotopes that are not radioactive with neutrons, protons, and other subatomic particles. See half-life. 2. (Often simply activity.) Rate of decay of a radioactive isotope. The unit of radioactivity is the curie.

The spontaneous decay of certain rare, unstable, atomic nuclei into more stable atomic nuclei. A natural by-product of this process is the release of energy.

The emission of energy due to changes in the nucleus of an atom. Such spontaneously released radiation is a characteristic of certain elements and at some levels can be harmful.