The number of ______ is equal to the difference between the mass number of the atom and the atomic number.

The atom is composed of the proton, the neutron, and the electron. Protons and neutrons make up the nucleus of the atom, whereas the negatively charged electrons revolve around the nucleus. The number of protons found in the nucleus equals the number of electrons that surround it Protons and neutrons have nearly equal masses, but they differ in charge. Protons : • The number of protons within the nucleus of a given atom is equal to the atomic number of the corresponding element.  For example, the atomic number of helium is two. Therefore, the number of protons is also two. Neutrons : • The number of neutrons within the nucleus of a given atom can be found by subtracting the atomic number from the atomic mass i.e difference between the mass number of the atom and the atomic number.