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.
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- i·so·top·ic [ahy-suh-top-ik], /ˌaɪ səˈtɒp ɪk/, adjective
- i·so·top·i·cal·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024
How to use isotope in a sentence
The minerals in the water contain trace amounts of uranium, which gradually decays into different uranium isotopes and eventually into a completely different element, thorium.This painted pig is the world’s oldest figurative art | Kiona N. Smith | January 15, 2021 | Ars Technica
The thousands of meteorites in NASA collections can be divided into two main classes, based on their isotopes—the relative amounts of the same elements with different numbers of neutrons.The Sight of Jupiter and Saturn Together Is a Beautiful Thing - Facts So Romantic | Sean Raymond & Sebastiaan Krijt | December 21, 2020 | Nautilus
The isotopes in the Bom Jesus tusks revealed that these elephants lived in a mix of forests and savannas.Ivory from a 16th century shipwreck reveals new details about African elephants | Maria Temming | December 17, 2020 | Science News
The researchers gave the critters a cocktail of chemicals labeled with isotopes, forms of elements having different masses.These Arctic squirrels recycle bits of their own bodies to survive winter | Carolyn Wilke | December 16, 2020 | Science News
Next, the researchers used the oxygen isotopes in the peat to track the waxing and waning of the region’s sea ice over thousands of years.Bering Sea winter ice shrank to its lowest level in 5,500 years in 2018 | Carolyn Gramling | September 3, 2020 | Science News
Deuterium is an isotope of hydrogen containing a proton and neutron in its nucleus, while normal hydrogen has only a proton.
After eight years, traces of the isotope are expected to be extremely low.
The next step was to test whether Arafat had actually ingested or inhaled a quantity of the suspect isotope.
One of the isotopes of fission products, when fuel melts, is an iodine isotope, and it goes in your body through your thyroid.
All we've been able to find is some strange isotope but we don't know how to reproduce it or synthesize it.Make Mine Homogenized | Rick Raphael
Well, heavy water is made of one atom of oxygen plus two atoms of deuterium, which is the first isotope of hydrogen.The Caves of Fear | John Blaine
Why nail the "power metal" down to an isotope of gold with an atomic weight of 197?Despoilers of the Golden Empire | Gordon Randall Garrett
There must be another one in either wing, for the isotope plant and the cartridge-case plant.The Cosmic Computer | Henry Beam Piper
An isotope is just a different variety of the ordinary kind of atom in each element.The Caves of Fear | John Blaine
British Dictionary definitions for isotope
one of two or more atoms with the same atomic number that contain different numbers of neutrons
- isotopic (ˌaɪsəˈtɒpɪk), adjective
- isotopically, adverb
- isotopy (aɪˈsɒtəpɪ), noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for isotope
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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Cultural definitions for isotope
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.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.