Final answer:
Noble gases have high ionization energies due to their filled outer subshells, which make them exceptionally stable and unreactive. They follow the octet rule with full valence shells, having no inclination to react under normal conditions. Significant energy is needed to remove an electron from their stable configuration.
Step-by-step explanation:
The Noble gases, such as helium, neon, argon, and others, indeed have large ionization energies, but not ionization energies of 0. This misunderstanding might arise from the stability of noble gases, which have filled outer subshells (electron configurations) making them particularly unreactive.
The octet rule helps explain their stability; noble gases like neon have an electron configuration that constitutes a full outer shell, which is highly stable and does not need additional electrons. As a result, they have high ionization energies because it requires considerable energy to remove an electron from a stable, filled valence shell. In contrast, other elements tend to lose, gain, or share electrons to achieve the noble gas configuration.
Because of their filled valence shells, noble gases also have no formal charge typically and don't form compounds easily. They can be forced into chemical compounds only under specific conditions involving high pressure and temperature.