Other forms: isotopes
An isotope is a version of an element carrying a different number of neutrons — same element, different weight. Carbon-12 and carbon-14 are both plain carbon: one is what you are made of, the other is what dates the bones in the museum.
Isotopes of one element behave alike in chemistry, because the number of protons — the thing that makes it that element — has not changed. You name them with the number after the word: uranium-235, hydrogen-3, carbon-14. Some are stable and sit there for ever; others are radioactive and break down, which makes them useful in medicine, dating and power stations, and dangerous in the wrong quantity. Do not mix isotope up with ion: an ion has gained or lost electrons and carries a charge, while an isotope has gained or lost neutrons and carries extra weight. The adjective is isotopic, and isotopic analysis is how a laboratory works out where a fish, a bone or a bottle of wine came from.
1nounisotopeOne of two or more forms of an element whose atoms have the same number of protons but different numbers of neutrons.
“Uranium has several isotopes, and only one of them is used in reactors.”
isotope is a form of a chemical element.
The name says same place: iso for same, tope from the Greek word for place, because every isotope of an element sits in the same box of the periodic table. It was coined by Margaret Todd in 1909 and used in public for the first time on 27 February 1913, by the English chemist Frederick Soddy.
From iso + tope, because the different isotopes of an element always occupy the same place in the periodic table. The term was coined by Margaret Todd in 1909 and first used publicly on February 27, 1913 by English chemist Frederick Soddy.
Etymology from Wiktionary, CC BY-SA