\textbf{209-} In which molecule, the ratio of the number of bonding electron pairs in the non-bonding layer of atoms to the number of bonding electron pairs is greater than the other three compounds?
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(1) Xenon(IV) fluoride \qquad (2) Nitrogen trifluoride \qquad (3) Sulfur trioxide \qquad (4) Carbon disulfide
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