Answer:
Atomic neutron mass electron number
Explanation:
Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom.
The term isotope is formed from the Greek roots isos ("equal") and topos ("place"), meaning "the same place".
The answer is D . I hope this help you :) .
