What term describes atoms of the same element that have the same number of protons but different masses due to varying numbers of neutrons?

The term that describes atoms of the same element with the same number of protons but different masses due to varying numbers of neutrons is isotopes. Isotopes are essential in understanding atomic structure and nuclear chemistry because they demonstrate how the same element can exist in multiple forms.

For example, carbon has isotopes such as carbon-12 and carbon-14; both have six protons (making them carbon), but carbon-12 has six neutrons while carbon-14 has eight neutrons. This difference in neutrons leads to variations in their atomic mass and can affect their stability and behavior in chemical reactions.

The distinction from other terms is significant. Ions refer to atoms that have gained or lost electrons, resulting in a net electric charge. Molecules are groups of two or more atoms that are chemically bonded together, which could include atoms of different elements. Compounds are substances formed from two or more different elements that are chemically bonded in fixed proportions. Thus, isotopes specifically relate to variations of the same element based on neutron count, making it the correct and precise answer.