Question

question 20 (1 point)
isotopes of an element have nuclei with
the same number of protons, but different numbers of neutrons.
the same number of protons, and the same number of neutrons.
a different number of protons, and a different number of neutrons.
a different number of protons, and the same number of neutrons.
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Explanation:

Isotopes are defined as atoms of the same element that have the same number of protons (which determines the element's atomic number) but different numbers of neutrons (which affects the atomic mass). So we analyze each option:

• Option 1: Matches the definition of isotopes (same protons, different neutrons).
• Option 2: Same protons and same neutrons would be the same isotope, not different isotopes.
• Option 3: Different protons would mean different elements, not isotopes of the same element.
• Option 4: Different protons mean different elements, so this is incorrect for isotopes of the same element.

Answer:

A. the same number of protons, but different numbers of neutrons.