Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.
The first ionization enthalpies for two isotopes of the same element are expected to be the same.
Isotopes of an element have the same number of protons and electrons, meaning they share the same electronic configuration and nuclear charge. Since ionization enthalpy depends on the attraction of electrons towards the nucleus and the repulsion of electrons from each other, these factors remain identical for both isotopes. Therefore, the energy required to remove an electron from the ground state of the isolated gaseous atom will be the same.
Explanation
Ionization enthalpy represents the energy required to remove an electron from an isolated gaseous atom in its ground state. The factors affecting it are the attraction of electrons towards the nucleus and the repulsion of electrons from each other. Isotopes only differ in their number of neutrons, which does not alter the nuclear charge (protons) or the electronic configuration. Thus, the attraction and repulsion forces acting on the electrons remain unchanged, resulting in the same first ionization enthalpy.