8. What quantities vary between isotopes of an element?


A. neutrons and electrons

B. neutrons and atomic mass

C. protons, electrons, and atomic mass

D. protons, electrons, and atomic number 2 columns


9. Which of the following is/are TRUE only of the isotopes of an element?


I. The same mass number

II. The same number of electrons

III. The same number of neutrons but different numbers of protons

IV. The same number of protons but different numbers of neutrons


A. I only B. IV only C. II and III only D. II and IV​