Question

multiple choice question
the term isotope describes

two or more atoms with the same atomic number but different mass numbers
two or more atoms with the same number of electrons but different numbers of neutrons
two or more atoms with the same mass number but different atomic numbers

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Explanation:

Isotopes have same number of protons (hence same atomic number) and different numbers of neutrons, resulting in different mass numbers.

Answer:

two or more atoms with the same atomic number but different mass numbers