What is an isotope?

An isotope is defined as a variant of a particular chemical element that contains the same number of protons but differs in the number of neutrons. This difference in neutrons leads to variations in atomic mass, but the chemical properties of the isotopes remain largely similar because they have the same number of electrons and, consequently, the same electronic configuration.

The relevance of this definition is significant in various fields like chemistry and physics, where isotopes play crucial roles in applications such as radiocarbon dating, medical imaging, and understanding nuclear reactions.

In contrast to the correct definition, the other choices describe different characteristics that do not accurately define isotopes. For instance, different elements involve distinct atomic numbers, which is not the case for isotopes of the same element. Similarly, variations in charge pertain to ions, and bonding relates to molecules formed by atoms rather than alterations in neutron count.