[Gingi]

Hi there guys,

Just found this site and I'm very excited about it. I have a number of somewhat theoretical questions about stuff I don't understand. I will appreciate anyone who will take the time to help me with the following questions. Obviously, I think it'll be wiser to list them all under one topic and not open a new topic for each questions:

1) Regarding the strentgh of chemical bonds. I do understand the intramolecula bonds are stronger than intermolecular bonds - so for example, ionic bond is stronger than hydrogen bond. But - among ionic bonds - how do I know how to quantifiy the strenght of an individual ionic bond? Does it have to do with their oxidation number? I have the same question regarding hydrogen bonds - does the strength of the H-bond (which is essentaly a dipole-dipole type of bond, right?) have to do with the dipole moment, therfore the electronegative?

2) In high school, and college level gen. chem. classes, people tend to ascribe only N, O, F as elements which are capable of H-bonding. Is that right? I mean I can't see a reason my S (which is chemically a lot like O) can do it also ? Maybe the degree of the bonding is weaker (smaller Electronegative?). Can someone clarify it for me please?

THANKS YOU VERY MUCH GUYS !

Gingi

[kizzler85]

As i remember there are there things that affect ionic bonding strength.
1. Charge of ion (greater the charge the greater the strength)
2. Ionic radius (smaller distances between bonding atoms create stronger bonds)
3. The greater the magnitude of the dipole moment (larger differences in EN's create stronger bonds)

There are other electronegative atoms that can form hydrogen bonds, but they are generally not discussed. The strength of hydrogen bonding is determined by its ability to donate a hydrogen bond for H bonding, but also its ability to accept an electronegative atom in subsequent H bonding. Water has excellent H bonding strength because it can form multiple H bonds per molecule. Each lone pair on oxygen can form a H bond with another water molecule. This is due to the small size of the molecule as larger molecules cannot form these unique water H bonds. It follows that most OH groups can form strong H bonds.