Explanation for exception in a trend? - Chemistry

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SUMMARY

The boiling point of elements generally increases from groups 14 to 16 in the periodic table, with a notable drop from group 16 to group 17. This decrease is attributed to the molecular structure of group 17 elements, which consist of diatomic molecules leading to weaker London dispersion forces due to fewer protons. Additionally, the higher-than-expected boiling points of ammonia (NH3), water (H2O), and hydrogen fluoride (HF) are explained by hydrogen bonding, which significantly influences their boiling points compared to other molecules in the same period.

PREREQUISITES
  • Understanding of periodic trends in boiling points
  • Knowledge of molecular forces, specifically London dispersion forces and hydrogen bonding
  • Familiarity with group classifications in the periodic table
  • Basic chemistry concepts related to molecular structure
NEXT STEPS
  • Research the molecular structure and properties of ammonia, water, and hydrogen fluoride
  • Study the concept of hydrogen bonding and its effects on boiling points
  • Explore periodic trends in other groups of the periodic table
  • Learn about intermolecular forces and their impact on physical properties of substances
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Chemistry students, educators, and anyone interested in understanding molecular interactions and periodic trends in boiling points.

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Homework Statement


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Homework Equations

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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