Which type of ionization energy is always greater than the preceding ionization energies?

The Nth ionization energy refers to the energy required to remove the Nth electron from an atom or ion. As you progress through the ionization energies (1st, 2nd, 3rd, and so on), each subsequent ionization energy is greater than the one before it when considering a specific element. This trend occurs because, once the first electron is removed, the remaining electrons experience a stronger effective nuclear charge and increased electron-electron repulsion.

This means that removing additional electrons requires more energy due to the reduced repulsion among the remaining electrons and the increased attraction by the positively charged nucleus. Therefore, as one continues to remove electrons, it consistently becomes more difficult to remove the next electron, leading to the conclusion that the Nth ionization energy is always the largest compared to the preceding values.

In summary, the correct answer is that the energy required for the Nth ionization is always greater than that of the preceding ionization energies because the effective nuclear charge on the remaining electrons increases as electrons are sequentially removed. This trend holds true for every successive ionization in a given atom.