The definition of an isotope is an element with similar chemical make-up and the same atomic number, but different atomic weights to another or others.
An example of an isotope is Carbon 12 to Carbon 13.
One of two or more atoms having the same atomic number but different mass numbers.
Any of two or more forms of an element having the same or very closely related chemical properties and the same atomic number but different atomic weights (or mass numbers)
U-235, U-238, and U-239 are three isotopes of uranium.
(topology) To define or demonstrate an isotopy of (one map with another).
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 .
One member of a family of chemical elements that has the same chemical properties (the same atomic number) but differs in mass. Isotopes have the same number of protons and electrons, but a different number of neutrons. The mass is determined by the total number of nucleons (neutrons and protons). See allotrope.
Origin of isotope
Coined in 1914 by British chemist Frederick Soddy from Ancient Greek ἴσος (ísos, “equal; same”) and τόπος (tópos, “place”), because the different isotopes of a chemical element always occupy the same position in the periodic table of elements. Compare the synonymous Icelandic word samsæta.