isotope
n. countablen. one of the different forms of a chemical element. While they have the same number of protons, they have a different number of neutrons, which makes some heavier than others.
n. one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table but different atomic masses and physical properties.
Carbon-14 is a famous isotope used to find the age of old objects.
Scientists analyzed the oxygen isotope ratios in the ice core to determine historical temperature fluctuations.
The medical team utilized a specific radioactive isotope for the diagnostic scan, ensuring the tracer would decay rapidly enough to minimize the patient's overall radiation exposure.
From iso- (“equal”) + -tope (“place”), because the different isotopes of an element always occupy the same place in the periodic table. The term was coined by Scottish doctor Margaret Todd in 1909 and first used publicly on February 27, 1913 by English chemist Frederick Soddy.
Possible back-formation from isotopy.
Often used in the plural when discussing the various forms of a single element.