One of two or more nuclides that are chemically identical, having the same number of protons, yet differ in mass number, since their nuclei contain different numbers of neutrons; individual isotopes are named with the inclusion of their mass number in the superior position (12C) and the atomic number (nuclear protons) in the inferior position (6C). In former usage, the mass numbers follow the chemical symbol (C-12). [iso- + G. topos, part, place]
- daughter i. an element produced by radioactive decay of another. See radionuclide generator, cow.
- radioactive i. an i. with an unstable nuclear composition; such nuclei decompose spontaneously by emission of a nuclear electronparticle) or helium nucleusparticle) and radiation (γ rays), thus achieving a stable nuclear composition; used as tracers and as radiation and energy sources. See half-life.
- stable i. a nonradioactive nuclide; an i. that shows no tendency to undergo radioactive decomposition.

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iso·tope 'ī-sə-.tōp n
1) any of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behavior but with differing atomic mass or mass number and different physical properties
iso·to·pic .ī-sə-'täp-ik, -'tō-pik adj
iso·to·pi·cal·ly -'täp-i-k(ə-)lē, -'tō-pi- adv
iso·to·py 'ī-sə-.tō-pē, ī-'sät-ə-pē n, pl -pies

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any one of the different forms of an element, possessing the same number of protons (positively charged particles) in the nucleus, and thus the same atomic number, but different numbers of neutrons. Isotopes therefore have different atomic weights. Radioactive isotopes decay into other isotopes or elements, emitting alpha, beta, or gamma radiation. Some radioactive isotopes may be produced artificially by bombarding elements with neutrons. These are known as nuclides and are used extensively in radiotherapy for the treatment of cancer.

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iso·tope (iґso-tōp″) [iso- + -tope] a chemical element having the same atomic number as another (i.e., the same number of nuclear protons) but possessing a different atomic mass (i.e., a different number of nuclear neutrons).

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  • isotope — [ izɔtɔp ] n. m. • 1922; angl. 1913; de iso et du gr. topos « lieu, place » ♦ Chacun des éléments de même numéro atomique (occupant la même place dans la classification de Mendeleïev), mais de masse atomique différente. Les isotopes 12, 13 et 14… …   Encyclopédie Universelle

  • Isotope —   [zu griechisch tópos »Platz«, »Stelle« (mit Bezug auf die gleiche Stelle im Periodensystem der chemischen Elemente)], Singular Isotop das, s, Atomkerne (Nuklide) mit gleicher Protonenzahl (Kernladungszahl, Ordnungszahl) …   Universal-Lexikon

  • isotope — isotope. См. изотоп. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • isotope — (n.) 1913, lit. having the same place, introduced by British chemist Frederick Soddy (1877 1956) on suggestion of Margaret Todd, from Gk. isos equal + topos place; so called because despite the different atomic weights, the various forms of an… …   Etymology dictionary

  • isotope — ► NOUN Chemistry ▪ each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei. DERIVATIVES isotopic adjective. ORIGIN from Greek isos equal + topos place , because the… …   English terms dictionary

  • isotope — [ī′sə tōp΄] n. [< ISO + Gr topos, place: see TOPIC] any of two or more forms of an element having the same or very closely related chemical properties and the same atomic number but different atomic weights (or mass numbers) [U 235, U 238, and …   English World dictionary

  • isotope — isotopic /uy seuh top ik/, adj. isotopically, adv. /uy seuh tohp /, n. Chem. any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in… …   Universalium

  • Isotope — This article is about the atomic variants of chemical elements. For the British jazz fusion band, see Isotope (band). Isotopes redirects here. For the minor league baseball team, see Albuquerque Isotopes. Isotopes are variants of atoms of a… …   Wikipedia

  • Isotope — Als Isotope bezeichnet man Nuklide in ihrem Verhältnis zueinander, wenn ihre Atomkerne gleich viele Protonen (gleiche Ordnungszahl), aber verschieden viele Neutronen enthalten. Die Isotope eines und desselben Elements haben also verschiedene… …   Deutsch Wikipedia

  • Isotope — Cet article possède des paronymes, voir : isotopie et isotrope. En physique nucléaire et en chimie, deux atomes sont dits isotopes si leur noyau a un nombre de protons identique mais un nombre de neutrons différent. Le nombre de protons dans …   Wikipédia en Français

  • isotope — n. a radioactive isotope * * * a radioactive isotope …   Combinatory dictionary

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