Chemistry

Chemistry

Problem

The ions N3−\text{N}^{3-}, Na+\text{Na}^{+}, Mg2+\text{Mg}^{2+}, and Al3+\text{Al}^{3+} each contain ten electrons but differ in nuclear charge. (a) Rank the four ions in order of increasing magnitude of the attraction between the nucleus and a selected 2p2p electron. Justify your ranking. (b) Using your ranking from part (a), predict which ion has (i) the largest and (ii) the smallest ionic radius. Explain the reasoning that connects electrostatic attraction to relative ionic size.
Intuitive explanation

These isoelectronic ions all have the same electron cloud, but their nuclei pull on those electrons with different strengths—that's the key to understanding their properties. The more protons in the nucleus, the stronger the attraction, which shrinks the ion and increases ionization energy. Think of it like the same number of people orbiting different-sized suns: a heavier sun pulls them in closer and holds them tighter.

Intuitive explanation

These isoelectronic ions all have the same electron cloud, but their nuclei pull on those electrons with different strengths—that's the key to understanding their properties. The more protons in the nucleus, the stronger the attraction, which shrinks the ion and increases ionization energy. Think of it like the same number of people orbiting different-sized suns: a heavier sun pulls them in closer and holds them tighter.

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