The mass number is equal to
A. the sum of the number of the electrons and protons.
B. the sum of the number of the neutrons and electrons.
C. the sum of the number of protons, neutrons, and electrons.
D. the sum of the number of protons and neutrons.
Answer:D
The mass number is equal to
A. the sum of the number of the electrons and protons. B. the sum of the number of the neutrons and electrons. C. the sum of the number of protons, neutrons, and electrons. D. the sum of the number of protons and neutrons.