Question

neutral atoms of all isotopes of a given element have the same____.
answer:
a number of protons and neutrons.
b number of neutrons.
c number of electrons.
d mass numbers.
e masses.

Explanation:

Isotopes are atoms of the same element with the same number of protons (which defines the element) but different numbers of neutrons. Since the element is neutral, the number of electrons equals the number of protons. The mass number and mass (which is related to mass number considering isotopic abundance) can vary among isotopes. But the number of protons (and thus electrons in neutral atoms) is constant for a given element's isotopes.

Answer:

C. number of electrons