Which of the following statements about isotopes is/are true?
a. Because isotopes have different numbers of neutrons, they have different mass numbers.
b. because neutrons determine an atom's chemical properties, isotopes of the same element are very different.
C. isotopes are atoms with the same number of protons but different numbers of neutrons.
d. isotopes have different atomic numbers because they have different numbers of protons.
e. Isotopes are chemically alike because they ahve the same number of protons and electrons.