[Kalibasa]

Hi! I've just started ochem and I'm working ahead a little.  I'm absolutely stumped by hybridization, though- I guess I'm just having trouble visualizing it.  My book was supposed to have animations on its website, but as I bought my book used I don't have the access code, and it will cost 50$.  Do you know of any links or online resources I can use to try to understand this concept? Animations or tutorials would be *wonderful*, if you know where I can find them

Here are some of the specific things that are confusing me:

1) When they talk about sp3 orbitals, are they referring to before or after the carbon bonds to the hydrogens? (for now I'm using methane)  I mean, what do the carbon orbitals look like before it bonds?
2) The p-orbitals by themselves look like dumbbells- does this mean the electrons in them move in a figure 8 around the nucleus? Because if they do, I don't see how they'd move in the hybrid orbitals, where the orbitals aren't at 180 degrees.
3) How does this business of hybrid orbitals relate to VSEPR theory? Is this just the detailed explanation for why bonds form in a tetrahedral shape? Because before they just told us that electron-electron repulsion was responsible for the shape

I'm sorry if I'm not being clear but I don't even know where to begin... An answer to any of these questions would *delete me* Thank you!

[MrTeo]

1) sp³ carbon doesn't even exist: when we talk about hybridization we have to remember that it only occurs when the atom considered is bonded to another atom or molecule. The bonding process and the hybridizing one happen at the same time.

2) As you can see p orbitals are space regions, so the electron doesn't move on the edge tracing an "8 figure" but we can find it in the whole orbital area. Moreover we don't know (and can't know, because of quantum mechanics and Heisenberg's principle) how the electron moves but we can only provide information about its position in space: the orbitals are areas in which the probability to find the electron (given by the square value of the wavefunction ) is bigger than 90-95%

3) Well, actually is not so "detailed"... it's only an approximation we use to represent molecules easily (and it's only a way to represent them, other than the VB theory, on which VSEPR is based, there's also the MO theory, much more complete and slighty more difficult to understand especially if you work with polyatomic structures)
Anyway hybridized orbitals, having all the same shape and energy are placed, according to VSEPR, to minimize this forces. Moreover if an orbital contains a lone pair we have to consider also the bending caused by this negative charge (just like in water: 105º instead of 109.5º). If we don't use hybridized orbitals it could be qute difficult to understand clearly how a carbon atom (with a 2s spheric orbital and three 2p) bonding to the 1s orbital of H would dispose in space.

Hope it's all clear now... if you need any other information , just ask