isotope

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Related to isotopies: isotropy

isotope

 [i´so-tōp]
a chemical element having the same atomic number as another (i.e., the same number of nuclear protons), but having a different atomic mass (i.e., a different number of nuclear neutrons).
radioactive isotope radioisotope.
stable isotope one that does not transmute into another element with emission of corpuscular or electromagnetic radiations.

i·so·tope

(ī'sō-tōp), An isotope is identified by its symbol preceded by a superscript numeral showing its mass number (12C). Alternatively the mass number may follow the symbol at the same level (C 12). When the name of the element rather than its symbol is used, the numeral must follow and not precede the name (carbon 12). Do not join the numeral to the symbol or the name with a hyphen. The atomic number of an element (the unvarying number of protons in its nucleus) may be shown by a subscript numeral preceding the symbol 6C).
One of two or more nuclides that are chemically identical, having the same number of protons, yet differ in mass number, because their nuclei contain different numbers of neutrons; individual isotopes are names with the inclusion of their mass number in the superscript position (12C) and the atomic number (nuclear protons in the subscript position (6C). In former usage, the mass numbers follow the chemical symbol (C-12).
[iso- + G. topos, part, place]

isotope

Imaging
An MRI term for atomic nuclei that contain the same number of protons, but differ in the number of neutrons in the nucleus of the atom for the element concerned.

i·so·tope

(ī'sŏ-tōp)
One of two or more nuclides that are chemically identical, having the same number of protons, yet differ in mass number, because 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).
[iso- + G. topos, part, place]

isotope

Chemically identical elements whose atomic nuclei have the same number of protons but different numbers of neutrons. The number of protons determines the number of orbital electrons and hence the chemical properties. Radioactive isotopes are called radionuclides. From the Greek iso -, equal and topos , place. Isotopes occupy the same place in the Periodic table of the elements.

isotope

any of the forms of an element having the same number of protons (atomic number) but a different number of neutrons (atomic mass). Some isotopes of an element may be radioisotopes (e.g. 12C is not radioactive while 14C is) and yet can function normally in biological material. Isotopes can thus be ‘tagged’ (using suitable detection devices such as geiger counters and autoradiography) as biochemical processes occur. See HALF-LIFE, AUTO RADIO GRAPH.

Isotope

An unstable form of an element that gives off radiation to become stable. Elements are characterized by the number of electrons around each atom. One electron's negative charge balances the positive charge of each proton in the nucleus. To keep all those positive charges in the nucleus from repelling each other (like the same poles of magnets), neutrons are added. Only certain numbers of neutrons work. Other numbers cannot hold the nucleus together, so it splits apart, giving off ionizing radiation. Sometimes one of the split products is not stable either, so another split takes place. The process is called radioactivity.

i·so·tope

(ī'sŏ-tōp)
One of two or more nuclides that are chemically identical, having the same number of protons, yet differ in mass number, because their nuclei contain different numbers of neutrons.
[iso- + G. topos, part, place]
References in periodicals archive ?
Le premier peut-etre dit referent actuel, l'autre etant le referent virtuel >>; (11) elle repose sur une rupture d'isotopies.
Dans ses deux exemples nous relevons l'isotopie de la nature : ete--automnejardinpetales de roses--mer revelent une veine romantique peu exploitee dans le roman beur.
The movement across the dividing space between the lovers is given clear sexual overtones (to be described as isotopies) in phrases such as "fiery", "pushing prow", "quench", "warm", "quick sharp scratch", "blue spurt" (I.
The transcendent ideal quality of this world is constituted by the pervasive isotopies of the mythic (the classical Mediterranean world) and the fantastic in such words as "Dryad" (1.7), "Flora" (I.
Il ne reste pius, au niveau du recit, qu'a creer une double isotopie qui accueille le lecteur dans l'incipit, comme nous le montrerons pius loin, et a placer des traits descriptifs a posteriori pour que le conte soit lisible d'une maniere univoque.
Dans ce cas, il s'agit tout simplement d'un scenario plutot sinistre illustrant l'adage "tel est pris qui croyait prendre." Pourtant, comme nous le verrons pius tard, il y a une isotopie juive qui donne au texte une lecture fortement univoque, bien que cette derniere se cache, si l'on peut dire, derriere differents niveaux de narration.
The concepts of actant and actor enable the establishment of two classes of discursive isotopies: predicative and figurative, thematic, affective isotopies etc.
In Anghel's choreographic adaptation, these major thematic isotopies from Shakespeare's text enable the subsuming of the kinesic figures under two predicative isotopies by means of these, two distinct actantial categories, the adjuvant and the opponent, are manifested.
Cela revient a dire qu'a chaque isotopie retenue correspond une aspectualite.
We would anticipate, then, that the details thus arranged according to the heuristic paradigm would reveal deep-structure patterns perhaps suggesting some governing themes, or isotopies, a process these models have not always proven successful in stimulating.
D'abord, peut-etre, en emaillant le recit de notations ou de peripeties propres a y introduire une isotopie de l'irrationnel -- voire, asymptotiquement, du fantastique -- qui le soustrait en partie au systeme de l'illusion realiste pour le rattacher a une autre forme (generiquement determinee) de vraisemblable.
Du point de vue rhetorique, cette dualite permet la cohabitation, et meme la juxtaposition, de deux isotopies. En effet, le narrateur detaille d'une part le travail de la bague et les nuances insaisissables de la gemme, indexant sa description sur l'isotopie du luxe et de la joaillerie; d'autre part il documente les effets du poison, et met en jeu l'isotopie de la mort envisagee dans ses aspects physiologiques.