oxygen_ranking
plain-language theorem explainer
Oxygen with atomic number 8 has electronegativity ranking 3/4 under the valence-fraction definition. Chemists checking periodic trends against the RS shell-closure model would cite this for direct validation. The proof reduces the ranking expression by unfolding valence count and period length, then evaluates the resulting fraction numerically.
Claim. For the element with atomic number $Z=8$, the electronegativity ranking equals $3/4$, where the ranking is the ratio of valence electrons to the length of the current period.
background
Electronegativity ranking is the ratio of valence electrons to period length. Valence electrons count the electrons beyond the previous noble-gas closure; period length is the span from previous to next closure. These functions encode the periodic boundaries that determine shell filling.
proof idea
The term proof first simplifies the ranking using the definitions of valence electrons, period length, and the two closure functions, then applies numerical normalization to obtain the concrete fraction 3/4.
why it matters
The result confirms the predicted rise in electronegativity across a period as the valence fraction increases toward closure. It supports module-level ordering statements such as fluorine exceeding oxygen and aligns with the RS claim that electronegativity follows shell distance modulated by period length.
Switch to Lean above to see the machine-checked source, dependencies, and usage graph.