how is the mass number calculated for an atom involved in nuclear fusion?
A. it is the number of protons plus neutrons
B. it is the number of protons plus electrons
C. it is the number of neutrons
D. it is the number of electrons
A. it is the number of protons plus neutrons
The mass number of an atom is calculated by adding the number of protons and neutrons in the atom's nucleus. In nuclear fusion, atoms combine to form a heavier nucleus, and the total number of protons and neutrons in the resulting nucleus will determine the mass number of the new atom.