[omkar]

will the bonded electrons revolve?ifso,around which atom will they  revolve?
around more electronegative atom
around less electronegative atom

  I will be thankful to the one who explain about it.

[macman104]

What do you think?  What is the definition of electronegativity?  What does it mean if an atom is more electronegative?

[omkar]

will the bonded electrons revolve?ifso,around which atom will they  revolve?
around more electronegative atom
around less electronegative atom

  I will be thankful to the one who explain about it.

What do you think?  What is the definition of electronegativity?  What does it mean if an atom is more electronegative?

                                                                                                                                                                                                                   Actually  I was trying to ask that whether the bonded electrons will revolve just like electrons in an atom.If not,will the molecule exist? Because  an atom doesnot exist with stationary electrons I think that electrons should revolve.let me consider an eg. of C-H bond.as c is more electronegative,it should attract bonded pair.In order to revolve,the bond must be broken.but practically we are not observing it.So,pair must revolve.Will it happen in covalent bond?                                                                                 

[cliverlong]

Do you mean the following?

Yes electrons are always moving.

Remember as they are small and fast they exhibit both particle and wave properties.

(I am not an expert on this ...) by wave mechanics the electron can be represented by a standing(?) wave around the nucleus. There can be different standing wave around a hydrogen nucleus corresponding to different energy levels. I believe the introduction of more protons in the nucleus and more atoms makes the exact calculation of these waves impossible.

Also, looking at the "shape" of s, p, d, f orbitals around an atom define regions of probaility where an electron in a certain energy state will "be" around a nucleus. But, Heisenberg's uncertainty principle means you CANNOT say exactly where an electron will be and know its momentum exactly. The standing wave is an extreme version of this where you can't point to any single position for the electron.

So I guess the molecular orbitals (if that is a good model) that are formed when atoms bond the electrons still exhibit this dual nature, they move and the proability of finding them in a particular location can only be expressed by a probability function smehow calculated from the molecular orbital. How that calculation is done, I do not know.

Anyone else have a better / more accurate description because it is a topic I need to understand better.

Clive

[macman104]

Omkar, I'm sorry, I'm still not clear on what you're asking.

[omkar]

Consider a C-H bond.Single electron of H is now in bonding with C.Now my question is that around which atom does H's electron move?My doubt is that if electrons revolve around their corresponding atoms,bond should be broken.If they remain stationary,will the individual atoms exist?

[cliverlong]

In the simple Rutherford-Bohr(?) model of the atom, electrons move around the nucleus of atoms in orbits at distances from the atom.

Can I rephrase your question as follows?
Are you asking "where are the electrons located in a molecular bond in analogy with the model of the position of electrons around an atom?"


Adding Planck's quantum ideas electrons are considered to be orbiting in fixed energy levels.

Adding wave mechanics and uncertainty electrons are no longer in fixed orbits but described by wave functions with probability. So you can't ask where an electron in a molecule is, and it certainly isn't stationary - although the dot and cross diagrams imply they are - all you can say is there is a molecular orbital model from which you can calculate the probability of the electrons from the constituent atoms somehow being "smeared" over the molecule in a way that leads to a stable or lowest energy structure.

The images I have in my mind are:

http://home.hiroshima-u.ac.jp/fpc/oguchi/graphics/mol-images.html
the diagram of acetylene (ethyne) in http://en.wikipedia.org/wiki/Molecular_orbital
and the molecular orbitals of nirtogen in the amazing animations in http://winter.group.shef.ac.uk/orbitron/MOs/N2/2pz2pz-sigma-star/index.html

Also Fig 8.9 here
http://www.chemistry.mcmaster.ca/esam/Chapter_8/section_5.html#Fig_8-9.
gives some suggestion that in bonds you can only map electron density not electron location or fixed orbits.

I think it's a very mathematical subject of which I know only a few fragments. If anyone want sto correct any gross errors I have written, I would welcome that to improve my understanding.


Clive

[cliverlong]

Another go

If your question means this ...

"Does the bonding pair of electrons move around both of the nuclei, or does it stop between the two atoms?"

then I suggest you read this ...

http://www.chemguide.co.uk/atoms/properties/orbitsorbitals.html#top

Where that question is posed and addressed


Clive

[omkar]

Then how can it be explained for co-ordinate covalent bonds?

[cliverlong]

Then how can it be explained for co-ordinate covalent bonds?

What is the "it" that needs explaining?

I find your questions difficult to understand.

Did you find the reference I gave to chemguide relevant to what I think your original question was?

Clive

[omkar]

Thankyou.You got my question and gave the suitable explanation.Actually the site you adviced to see is not opening.Now my question is how can you explain  thesame phenomenon for co-ordinate covalent bonds?

[cliverlong]

I think everything I have written (if correct) about covalent bonds also applies to co-ordinate / dative bonds.

I think of a co-ordinate/dative bond as a covalent bond where the electron pair comes from one atom (the donor) rather than one electron coming from each atom. The classic example is when a proton H+ attaches to ammonia to make an NH4+ ammonium ion.

http://en.wikipedia.org/wiki/Coordinate_covalent_bond

Can you explain why you think the same explanation about electron "position" does not apply in the co-ordinate case? Then I can understand where you are coming from.

Which of the various sites I suggested you read is not opening? All of them?

Clive

[Astrokel]

Although i did not follow this thread(ain't sure what you are asking), but i read before that dative bonding is no difference from any covalent bond once it is formed.