isotope

[ ahy-suh-tohp ]

noun

, Chemistry.

1. 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 the nucleus, or different atomic weights. There are 275 isotopes of the 81 stable elements, in addition to over 800 radioactive isotopes, and every element has known isotopic forms. Isotopes of a single element possess almost identical properties.

isotope

/ ˌaɪsəˈtɒpɪk; ˈaɪsəˌtəʊp; aɪˈsɒtəpɪ /

noun

1. one of two or more atoms with the same atomic number that contain different numbers of neutrons

isotope

/ ī′sə-tōp′ /

1. One of two or more atoms that have the same atomic number (the same number of protons) but a different number of neutrons. Carbon 12, the most common form of carbon, has six protons and six neutrons, whereas carbon 14 has six protons and eight neutrons. Isotopes of a given element typically behave alike chemically. With the exception of hydrogen, elements found on Earth generally have the same number of protons and neutrons; heavier and lighter isotopes (with more or fewer neutrons) are often unstable and undergo radioactive decay .

isotope

1. In physics , different forms of the same element , with nuclei that have the same number of protons but different numbers of neutrons . Isotopes are distinguished from each other by giving the combined number of protons and neutrons in the nucleus. For example, uranium 235 is the isotope of uranium that has 235 protons and neutrons in its nucleus rather than the more commonly occurring 238. All elements have isotopes.

Derived Forms

• ˌisoˈtopically, adverb
• isotopic, adjective
• isotopy, noun

Other Words From

• i·so·top·ic [ahy-s, uh, -, top, -ik], adjective
• iso·topi·cal·ly adverb

Word History and Origins

Origin of isotope¹

First recorded in 1910–15; iso- + -tope, from Greek tópos “place”; Utopia ( def )

Word History and Origins

Origin of isotope¹

C20: from iso- + Greek topos place

Example Sentences

That is the stark warning from experts who have said the lack of medical radioactive isotopes available in the UK means delays in tests to diagnose cancer.

From BBC

A good thing to note is that deuterium, a stable isotope of hydrogen, is much less expensive and can be found in seawater.

From Los Angeles Times

His research there focuses on how certain isotope compositions in clay minerals could indicate past life in samples brought back from Mars.

From Los Angeles Times

Vaksmaa: "These so-called 13C isotopes remain traceable in the food chain. It is like a tag that enables us to follow where the carbon goes. We can then trace it in the degradation products."

From Science Daily

Unlike other rare earth elements, only minute quantities of synthetic promethium are available because it has no stable isotopes.

From Science Daily