Finding Bond Length

[705914414]

How do you find the bond length? What does this have to do with melting point?

[Alexa Garcia]

The stronger the bond length is the higher the melting point will be.

[505989311]

There's no way to find the bond length if the question doesn't give you the values. You also don't need bond lengths for most questions. You just need to know relative bond lengths and how they affect different properties such as reactivity, melting/boiling points, both strength, etc. Generally this would consist of knowing that bond lengths are affected by bond type (triple bonds are shorter than double bonds which are shorter than single bonds) and also affect by atom size (HF is a shorter bond than HCl because F has smaller atomic radius)

[Alex Denman 2G]

Hey there!
Currently in this class, we do not need to figure out how to find bond length. We just need to know the trends of bond length. The first trend is that triple bonds<double bonds<single bonds. Single bonds hold the atoms together less tightly, so they have the longest bond lengths. Secondly, bond length increases as the size of the atoms increase. For example, HF will have a stronger bond than HI because iodine is a much larger atom (this means that the bond between H and I is more easily broken, making HI a much stronger acid than HF). When it comes to the relation between bond length and boiling point, I believe there generally is none. Boiling and melting refer to the breaking of intermolecular forces, i.e. dispersion, hydrogen, and dipole-dipole. This is why we see that water has a much higher melting and boiling point than methane. The molecules are both small and seemingly innocuous, but water can form hydrogen bonds with itself, giving it relatively high boiling and melting points, given its size. Methane on the other hand only exhibits dispersion forces because it is nonpolar, and uncharged.

Hope this helped!