isotope Definition

isotope
noun

1. chem.
One of two or more atoms of the same chemical element that contain the same number of protons but different numbers of neutrons in their nuclei and therefore have the same atomic number and chemical properties, but different mass numbers and physical properties.

Derivative: isotopic
adj

Derivative: isotopically
adverb

Derivative: isotopy
noun

Etymology: Early 20c: from iso- + Greek topos place (ie on the periodic table).