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

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.

Other Word Forms

• isotopic adjective
• isotopically adverb
• isotopy noun

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

The FDA said multiple brands of frozen shrimp may be contaminated with cesium-137, a radioactive isotope.

From Salon

The researchers were able to measure carbon, oxygen, strontium and lead isotopes from the tooth which revealed changes to the animal's diet with the seasons and showed seasonal food sources came from different geological areas.

From BBC

Food and Drug Administration is warning people to avoid eating certain raw frozen shrimp sold in Walmart stores as the agency investigates possible contamination by Cesium-137, a radioactive isotope.

From Los Angeles Times

The US Food and Drug Administration said varieties of frozen shrimp sold under Walmart's Great Value label could have been exposed to a dangerous isotope in shipping containers.

From BBC

The isotopes had not even settled and already people were out there making confident claims about what had or had not transpired.

From Salon