An isotope is a variant of a particular chemical element which differs in neutron number, and consequently in atomic mass, but not in chemical properties. All isotopes of a given element have the same number of protons in each atom.
One common example of isotopes is carbon. Carbon-12, carbon-13, and carbon-14 are all isotopes of carbon, with 6 protons each but 6, 7, and 8 neutrons, respectively.
Understanding isotopes is important in various scientific fields, including chemistry, physics, and geology. Mastery of this topic will provide a strong foundation for understanding atomic structure and the behavior of elements in nature and in the laboratory.