Question

To obtain the most precise value of BE from the equation BE=[ZM(1H)+Nmn]c2−m(AX)c2, we should take into account the binding energy of the electrons in the neutral atoms. Will doing this produce a larger or smaller value for BE? Why is this effect usually negligible?

a) Larger; electrons contribute significantly to the mass.

b) Smaller; electrons contribute significantly to the mass.

c) Larger; electrons contribute minimally to the mass.

d) Smaller; electrons contribute minimally to the mass.

Answer 1

Taking into account the binding energy of the electrons in neutral atoms when calculating binding energy (BE) will result in a smaller value for BE because electrons contribute minimally to the mass. This effect is usually negligible due to the minor mass of electrons compared to nucleons.

Step-by-step explanation:

To obtain the most precise value of binding energy (BE) from the equation BE = {[Zm(1H)+Nmn]−m(X)} c², where Z represents the number of protons, m(1H) is the mass of a hydrogen atom, N is the number of neutrons, mn is the mass of a neutron, and m(X) is the atomic mass of the nuclide, we should indeed take into account the binding energy of the electrons in neutral atoms. Doing this will produce a smaller value for BE.

The reason why the effect of electron binding energy is usually negligible is that electrons contribute minimally to the mass in comparison to the mass of nucleons. This is because the mass of an electron is much smaller than that of a proton or a neutron. Therefore, when calculating BE for nuclei, the electron mass and their binding energy are typically omitted for simplicity as they have only a very minor effect on the total value.