Bond strength in order

[Ramil]

can someone organize bond strengths (ionic, covalent , and Hydrogen bonding) in order from increasing to decreasing strength.

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[redchesus]

Generally speaking: ionic > covalent > H-bond > dipole-dipole > van der Waals

of course the ionic/covalent distinction is purely made up by scientists and the strength really depends on the individual atoms involved

and the H-bond is actually a special type of dipole-dipole

 

[yuppers]

Strongest to weakest:
covalent >>>>>>> ionic >> ion-dipole = H-bonding > dipole-dipole >>>>> van der waals

Covalent bond is strongest by far since there is a sharing of electrons between two atoms.
Ionic is an electrical attraction between a metal and non-metal... much like the others types of interactions except stronger.

 

[UndergradGuy7]

I agree with yuppers a covalent is stronger than an ionic.

 

[redchesus]

Strongest to weakest:
covalent >>>>>>> ionic >> ion-dipole = H-bonding > dipole-dipole >>>>> van der waals

Covalent bond is strongest by far since there is a sharing of electrons between two atoms.
Ionic is an electrical attraction between a metal and non-metal... much like the others types of interactions except stronger.

I actually don't think you can say covalent is much much stronger than ionic. Ionic is the interactions between full charges, which I think you're underestimating. Like I said, there's a huge overlap, but I've always been taught that generally ionic > covalent.

Consider the fact that many ionic compounds are solids at room temp (NaCl, KOH, etc.) while the covalent ones are liquids or gases (HCl, CH4, etc.). KCN, for example is a powder, while CH3CN is a liquid. Solubility in water isn't indicative of bond strength btw.

 

[loveoforganic]

I believe what I'm about to say is correct, but if I'm mixing up bond strength with something else, let me know. I feel like bond strength might actually be a nondescript term that refers to multiple things, though.

The first post (Ionic > covalent > van der waals) is correct. You're mixing up what bond strength refers to. Bond strength refers to the energy required to homolyze a bond - e.g. break it up into radicals. Therefore, the bond strength (equivalen to bond energy?) of NaCl would be going to Na* + Cl*, not Na+ + Cl-

 

[Flapjacks]

You people talk as if these sort of facts are open to discussion. Please don't confuse a poster by trying to remember an answer that you don't know for sure.

lovefororganic/redchesus are correct.

 

[redchesus]

^ haha, well you know, it's science where everything is a theory

but more to the point, the reason I wasn't more firm is that in actuality, it's hard to say whether ionic or covalent bonds are stronger, it really depends the molecules you're comparing

but for the sake of (major) generalization for low level gen chem, I was taught ionic > covalent

 

[UndergradGuy7]

You people talk as if these sort of facts are open to discussion. Please don't confuse a poster by trying to remember an answer that you don't know for sure.

lovefororganic/redchesus are correct.

Then explain this:
http://people.seas.harvard.edu/~jones/es154/lectures/lecture_2/covalent_bond/covalent_bond.html

[SIZE=+1]The Covalent Bond: Covalent Bonds are the strongest chemical bonds, and are formed by the sharing of a pair of electrons.

[/SIZE][SIZE=+1]Also see here http://ocw.alfaisal.edu/NR/rdonlyre...6C967E-6DEF-4BE9-964C-6B5C64EA8C58/0/lec5.pdf

"Properties of Covalent Materials
Covalent bonds are the strongest of the chemical bonds."
[/SIZE][SIZE=+1]
[/SIZE]I think this is one of those things that is debatable. Comparing different compounds you will find some that some covalent are stronger than an ionic, but you will also find ionic ones that are stronger than covalent. Lets just say there is not much difference between a covalent and ionic bond. Afterall an ionic bond is only called ionic after the difference in electronegativities is greater than a certain number. Lets agree that they are both strong.
[SIZE=+1]

[/SIZE]

 

[Flapjacks]

Right but this isn't theoretical chemistry. And when its a multiple choice test, you can't sit there debating yourself.

A bond is "an electrical force linking atoms ." Ionic bonds form when the electronegativity is great than a difference of 2 on the Pauling Electronegativity chart [sic]. Covalent bonds involve electronegativities lower than a difference of 2.

 

[UCB05]

Right but this isn't theoretical chemistry. And when its a multiple choice test, you can't sit there debating yourself.

A bond is "an electrical force linking atoms ." Ionic bonds form when the electronegativity is great than a difference of 2 on the Pauling Electronegativity chart [sic]. Covalent bonds involve electronegativities lower than a difference of 2.

...which hints at the distinction between covalent and ionic as kinda arbitrary.

In order of bond energy,
H-F > H-H > H-I
C-F > C-C > C-Cl

If you want to say ionic bonds are stronger, I suppose you could, as the strongest ionic bond energy I could find was greater than the strongest covalent bond I could find. Still, there's a lot of room for variation, so if you want to know which is stronger, it would be most appropriate to also know what atomic bonds you're comparing.

One could also say covalent bonds are stronger in cases where triple bonds can be formed vs single ionic bonds, but there's a big difference there as well.

Consider the fact that many ionic compounds are solids at room temp (NaCl, KOH, etc.) while the covalent ones are liquids or gases (HCl, CH4, etc.). KCN, for example is a powder, while CH3CN is a liquid. Solubility in water isn't indicative of bond strength btw.

This is an intermolecular property, not related to intramolecular bond energy

 

[CaptainSSO]

^There is no such thing as a "single" ionic bond.

 

[Maygyver]

What's the difference in strength between nonpolar covalent and polar covalent bonds?

 

[loveoforganic]

within the same column, polar covalent is generally stronger than nonpolar covalent

 

[dentalWorks]

I don't believe you will get a question to ask you to compare the strengths of an ionic vs covalent bond (becaue they are both considered "strong" bonds).... meaning it takes ALOT OF ENERGY input to break them apart

On the other hand you got your "weak" bonds, things like H bonding, vander wal forces, dipole-dipole....

There is a good chance u'll get a question to ask you to compare "which is strong or weaker bond between": weak bond type vs strong bond type

 

[Flapjacks]

Breaking bonds gives off energy.

 

[dentalWorks]

Breaking bonds gives off energy.

That is not true at all. Not all bonds give off more energy than you supply them to initiate the breaking. If thats the case, you can create a car to run on table salt.

Strained bonds tend to give off energy when you break thier bonds (hydrocarbons is a good example), think about how much energy it takes to melt table salt

 

[Flapjacks]

Water is a universal solvent.

 

[UCB05]

Water is a universal solvent.

Stop trolling imo. On the other forums, too.