Final answer:
Neon (Ne) has the largest second ionization energy among the given elements.
Step-by-step explanation:
The atom of neon (Ne) has the largest second ionization energy among the given elements - Sodium (Na), Oxygen (O), Fluorine (F), and Neon (Ne). Ionization energy refers to the energy required to remove an electron from an atom. The second ionization energy is the energy required to remove the second electron from an atom. Since neon already has a stable electron configuration with a completely filled second energy level, removing an electron from it requires much more energy compared to removing an electron from any of the other given elements.