Explanation for exception in a trend? - Chemistry

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The discussion focuses on the trend of boiling points across groups 14 to 17 in the periodic table, noting a general increase followed by a drop from group 16 to 17. The initial explanation attributes this drop to the presence of fewer protons in group 17 molecules, resulting in weaker London dispersion forces. However, the conversation highlights that this explanation overlooks the higher-than-expected boiling points of ammonia, water, and hydrogen fluoride, which are influenced by hydrogen bonding due to their free electron pairs. Participants suggest that these interactions significantly affect boiling points, providing a more comprehensive understanding of the trend. Overall, the discussion emphasizes the importance of considering molecular interactions beyond simple atomic structure when analyzing boiling point trends.
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The Attempt at a Solution


I have to explain why the boiling point generally increases from groups 14-16 but drops from 16-17, my answer is that every molecule in the the 17th group has only two atoms, meaning there are less protons in the molecule causing a weak london dispersion force. I'm in a relatively low level so I think this answer may do but does anyone have a better explanation or an addition to mine? Any help is appreciated
 
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Boiling points increase is observed in all groups, the only exception being molecules from the first period.

Your explanation doesn't touch higher than expected boiling points of ammonia and water.

Hint: ammonia, water and hydrogen fluoride all have sticking out free electron pairs. Do you know any kind of interaction that could utilize them?
 
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