Final answer:
Isotopes are atoms of the same element with the same number of protons but varying numbers of neutrons, resulting in different mass numbers but similar chemical properties.
Step-by-step explanation:
The term for atoms of the same element that vary in the number of neutrons in their nuclei is called isotopes. By definition, isotopes are variants of a particular chemical element which differ in neutron count, while maintaining the same number of protons. Practically, this means that while they have the same atomic number (Z), they have different mass numbers (A), since the mass number is calculated by adding the number of protons and neutrons together. An example of isotopes can be observed in carbon, where the most common form has six protons and six neutrons (12C), but isotopes with seven (13C) and eight neutrons (14C) also exist. Though their atomic mass differs, isotopes of an element have very similar chemical properties because they contain the same number of protons and electrons.
Atoms of an element that contain different numbers of neutrons are called isotopes.Each isotope of a given element has the same atomic number but a different mass number (A), which is the sum of the numbers of protons and neutrons.An example of isotopes can be observed in carbon, where the most common form has six protons and six neutrons (12C), but isotopes with seven (13C) and eight neutrons (14C) also exist. Though their atomic mass differs, isotopes of an element have very similar chemical properties because they contain the same number of protons and electrons.