What contributes to the calculation of the mass number?
A. sum of protons and electrons
B. sum of electrons and neutrons
C. sum of protons and neutrons
D. sum of protons, neutrons, and electrons
Answer:C
What contributes to the calculation of the mass number?
A. sum of protons and electrons B. sum of electrons and neutrons C. sum of protons and neutrons D. sum of protons, neutrons, and electrons