isotope
Meaning of isotope: Isotopes are versions of the same element with differing neutron counts, some of which are used in medical imaging and treatment.
Definition of isotope
An isotope is one of two or more forms of the same chemical element whose atoms share an identical number of protons but differ in the number of neutrons within the nucleus. Because the number of protons determines which element an atom belongs to, isotopes of a given element behave nearly identically in ordinary chemical reactions despite differing slightly in mass.
Some isotopes are stable and do not change over time, while others are radioactive, meaning their nucleus is unstable and releases energy as it gradually transforms into a different, more stable configuration. Carbon 12, carbon 13, and carbon 14 illustrate this range, sharing six protons each but differing in neutron number, with carbon 14 being radioactive.
Radioactive isotopes are used in medicine for imaging, such as tracing how a substance moves through the body, and for certain treatments that rely on radiation delivered directly to targeted tissue.
Used in a sentence
A radioactive isotope was used to trace blood flow during the diagnostic imaging study.
Good to know
Not all isotopes are radioactive, so describing a substance as an isotope does not by itself indicate whether it emits radiation or is used for imaging or treatment.
Word origin
Where “isotope” comes from
Formed from Greek isos, meaning equal, and topos, meaning place, describing atoms that occupy the same position in the periodic table despite differing in mass.