Strengths of Intramolecular and intermolecular forces

Question

For intramolecular forces -- Ionic, Metallic, and Covalent -- I have seen sources that said that ionic bonds are stronger than covalent while others have said the opposite (example: ionic compounds dissociate in water but covalent molecules still stay as one so covalent bonds are stronger). Which one is correct?

Similarly I have also seen sources that said ionic bond is stronger than metallic bond and visa versa. Which one is correct?

I would appreciate if you could list the order of weakest to strongest.

Also, is electrostatic force a type of intermolecular force?

Thank you!

Answer 1

Based on your description, the frame of reference is ambiguous. What do you mean by "strong"?

In reality, the only true bonds are covalent. Ions have such a "strong" association between a positive and negative charge, they act like a bond. A similar mentality applies to metals.

Based on your argument, I could say covalent is weaker. If I expose methane gas to a heat source and some oxygen, the bonds will break to form water and CO2. If I expose table salt to the same conditions, nothing really happens.

Water, as a polar solvent, can easilty dissociate ions but not organics, like methane.

I think you speak of enthalpy when you talk about "strong". However, in reactions, another things is at play: entropy. Entropy and enthalpy work together through a concept called Gibb's Free Energy. It may take a lot of energy (enthalpy) to break a bond, but, from an entropic perspective, may be much more favorable.

Also, you have to look at the CHANGE in energy. If you separate two ions (Na and Cl), they will still have a low energy state dissolved in water. The same is not true for the H and C in methane. Hopefully, that has sparked the conversation enough to give you guidance on how to best explain your confusion.