Repulsive and Attractive Forces that influence chemical bonds?

[berry2]

Hi! This is a homework question that I'm supposed to answer but that I really do not understand. "Identify two repulsive forces and two attractive forces that influences the formation of chemical bonds between two atoms." I noticed that this question was already posted once at this website but I was not able to understand where the question went, so I'm posting it again.

I'm not sure if I'm just reading too much into the question or what but I read the question and I don't even know where to start. I tried looking up attractive and repulsive forces on the Internet but couldn't find any good sources. (I'm doing this through an independent learning centre, so I can't ask a teacher.) I do not recall reading any information on this subject in the last lesson,.

First, what are the two repulsive forces and two attractive forces that the question is asking about? How do van der Waals forces (they are attractive right?) and dipole-dipole forces, etc. fit in with this question?

I'd really appreciate any help. Thanks!

 

[Astronuc]

I don't know if you mean two types of attractive and repulsive forces or two examples of the same type. For example, the Coulomb forces associated with charges can be repulsive (for like charges +/+ or -/-) or attractive (+/-).

Then there are magnetic fields which can be repuslive for like poles (N/N or S/S) or attractive for opposite poles (N/S).

Chemical bonds are essentially related to E/M fields, which have to do with sharing of electrons. Within an atomic bonds, the forces derived from sharing electrons (+ nuclei attract - electrons) are balanced by the Coulomb repulsion of the nuclei (+/+).

Where is the other thread on this subject?

 

[Gokul43201]

Hi! This is a homework question that I'm supposed to answer but that I really do not understand. "Identify two repulsive forces and two attractive forces that influences the formation of chemical bonds between two atoms." I noticed that this question was already posted once at this website but I was not able to understand where the question went, so I'm posting it again.

Sound eerily familiar. Did I respond to the earlier thread? Got a link to it?

 

[berry2]

Here is the link to the previous thread: https://www.physicsforums.com/showthread.php?t=74752. As I said earlier, I get totally confused just reading this question, so I'm not even sure what it is really asking. But that is all the information I'm given to work with.

 

[Gokul43201]

0. A chemical bond is nothing but the result of electrostatic interactions between the charged particles in atoms.

1. There is no net force between the atoms in a molecule (if there was a net force, then by Newton's Third Law, we would see the atoms flying into or away from each other).

2. This does not mean there are no forces between the (parts of these) atoms. Clearly, if there are charges, they must attract or repel ohter charges. The only thing we can say is that the sum of these forces be zero.

3. What kinds of charges do you have in an atom? If you bring a pair of atoms close together, what effects will these charges have on each other?

 

[porter44]

attractive:
-nucleus of an atom and its own electrons
-nucleus of one atom and the electron clouds of another

repulsive:
- the negative electron clouds of two different atoms
- the positive nuclei of two different atoms

resource: Foundations of Chemistry text