Question

how do scientists determine the number of neutrons in an isotope of an atom? they divide the atomic mass by two. they add the number of electrons and protons. they subtract the atomic number from the atomic mass. they find the number of protons.

Explanation:

The atomic mass of an isotope is the sum of protons and neutrons. The atomic number is the number of protons. So, subtracting the atomic number (number of protons) from the atomic mass gives the number of neutrons.

Answer:

They subtract the atomic number from the atomic mass.