Final answer:
To order the species Ne, O²⁻, F⁻, Na⁺ from largest to smallest: O²⁻ is the largest due to more electron-electron repulsion, followed by F⁻, then Ne as an isoelectronic species with the same electron count but less positive charge than Na⁺, which is the smallest due to its greater nuclear attraction.
Step-by-step explanation:
The question asks to order the species Ne, O²⁻, F⁻, Na⁺ from largest to smallest in size. In general, the size of atoms and ions is influenced by their position on the periodic table and the number of electrons present. The trend indicates that atomic and ionic size increase as we move down a group and decrease as we move across a period. Hence, for ions with the same number of electrons (isoelectronic species), the size generally decreases with an increasing positive charge due to greater nuclear attraction.
Taking this into account, the ion size order from largest to smallest would be O²⁻ (large because it holds more electrons and therefore more electron-electron repulsion), F⁻, Ne (even though not an ion, as an isoelectronic species with the same electron count, it would be larger than Na⁺), and Na⁺ (smallest due to its greater positive charge minimizing the radius).
Thus, the correct order from largest to smallest in size is O²⁻ > F⁻ > Ne > Na⁺.