Understanding Melting Points for the Periodic Table

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    Melting Points
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Discussion Overview

The discussion centers around understanding melting points of various compounds in the periodic table, particularly focusing on the relationship between ionic and covalent bonds and the structure of the lattice in determining melting points. Participants seek clarification on how to interpret melting points and their variations among different compounds.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses difficulty in understanding melting points and seeks an explanation of their determination in the periodic table.
  • Another participant presents data on the solubility and melting points of sodium halides (NaF, NaCl, NaBr, NaI) and asks for an explanation of the trend in melting points.
  • Some participants propose that the trend in melting points is related to the ionic versus covalent character of the bonds, suggesting that NaF has a higher melting point due to its ionic nature.
  • Another participant challenges this view, stating that while bond energy is related to ionic/covalent character, the melting point is more influenced by the nature of the lattice structure, emphasizing that tightly packed lattices with similar ion sizes yield higher melting points.

Areas of Agreement / Disagreement

Participants express differing views on the factors influencing melting points, with no consensus reached on the primary reasons for the observed trends in melting points among the sodium halides.

Contextual Notes

The discussion includes assumptions about the relationship between bond type and melting point, as well as the importance of lattice structure, which may not be fully explored or resolved.

komal12
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hi

i am having a hard understanding melting points from my textbook. can someone please explain to me how they work and how you can determine melting points in the periodic table?
 
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Can anyone help me with this:

element solubility in water Melting

NaF 0.042 988
NaCl 0.357 801
NaBr 1.16 755
NaI 1.84 651

Explain the decreasing melting point from NaF to NaI?

I think it has to do with covalent and ionic bonds...because NaF is ionic it has a higher because its harder to pull the electrons apart and NaI more covalent so it has a lower melting point...am i close please help..!
 
Last edited:
Yeah, youre on the right track.
 
komal12 said:
Can anyone help me with this:

element solubility in water Melting

NaF 0.042 988
NaCl 0.357 801
NaBr 1.16 755
NaI 1.84 651

Explain the decreasing melting point from NaF to NaI?

I think it has to do with covalent and ionic bonds...because NaF is ionic it has a higher because its harder to pull the electrons apart and NaI more covalent so it has a lower melting point...am i close please help..!

No, you are not on the right track...

Bond energy tracks with ionic/covalent character but melting point is more related to the nature of the lattice that makes up the material. Neat, tightly packed lattices with equal size anions and cations will have a higher melting point than one with ions of different sizes. This is more important to melting point than the bond strength.

http://www.Newton.dep.anl.gov/askasci/chem00/chem00800.htm
 

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