Chemistry

Chemistry

Problem

Rank the isoelectronic species O2−\mathrm{O}^{2-}, F−\mathrm{F}^{-}, and Na+\mathrm{Na}^{+} in order of increasing ionic radius and justify your answer in one sentence.
Intuitive explanation

All three species have the same electron configuration (10 electrons), so the key is understanding how nuclear charge affects the size of an isoelectronic series. The nucleus pulls harder on the same electron cloud when it has more protons, so species with higher atomic number shrink. Compare the number of protons in each nucleus, then rank them accordingly.

Intuitive explanation

All three species have the same electron configuration (10 electrons), so the key is understanding how nuclear charge affects the size of an isoelectronic series. The nucleus pulls harder on the same electron cloud when it has more protons, so species with higher atomic number shrink. Compare the number of protons in each nucleus, then rank them accordingly.

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