What are electrons with the same number of protons but different numbers of neutrons called?

Electrons with the same number of protons but different numbers of neutrons are referred to as isotopes. This distinction arises because isotopes are variants of a particular chemical element that share the same atomic number (the number of protons), which means they belong to the same element, but they differ in their mass number due to the variation in neutron count.

The mass number of an atom is the total of protons and neutrons in the nucleus, so isotopes will have the same number of protons but differing numbers of neutrons, leading to differences in atomic mass. For example, carbon has isotopes like carbon-12 and carbon-14; while they both have 6 protons, carbon-12 has 6 neutrons, whereas carbon-14 has 8 neutrons. This definition makes isotopes crucial in various fields, including chemistry, physics, and even medicine.

Understanding this concept is important, as it underscores the role of neutrons in the stability and behavior of elements, yet it ensures we recognize that isotopes belong to the same element base defined by their proton count.