help! org chem

[dr.day]

I need help! I am studying for my first organic chem exam and do not understand sp3 hybridization. Its been about 7 years since gen chem and cannot remember anything about orbitals at all! Unfortunately, I don't have any gen chem books around to look at and am not sure it would make sense anyway. Can somebody please explain this stuff to me in plain English??

Thanks!

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[Raptor]

I would suggest that you first look in your textbook or a professor for help.
I just took my 1st organic chemistry last week and we had sp3 orbitals. First you have to understand what is hybridization. Hybridization is the "blending" of orbitals. A sp3 orbital has four sigma bonds that is bonded to a C atom. Those sigma bonds separate each other by 109.5 bond angle and has a tetrahedral molecular shape. Example of sp3 hybridization molecular is CH4 because hydrogen is bonded by 1 sigma bond 4 times to that C atom. If you understand sp2 and sp hybridizations then you should understand sp3 hybridization. Good luck on the test and don't panic, its just the first test (but you do want to do well on this test because it will be the easiest test of the semester)

 

[Raptor]

sorry it doesn't only have to be bonded to a C atom but any centralized atom

 

[Wahoo07]

You originally have one s orbital and three p orbitals (which are equivalent to each other, but different from the s orbital), for a total of four orbitals. Think of sp3 hybridization as the four orbitals coming together and forming four equivalent sp3 orbitals. Hope this helps.

 

[dr.day]

thanks for the quick response...I see I am not the only one home on a saturday night!
I guess the thing I can't remember is more about the orbitals...what is the the "s" orbital? the "p" orbital? It was so long ago that I learned that stuff. Aren't there also f and d orbitals? What do you think I need to know about this for the first test?
Thanks again!

 

[kidsmd]

Remember that the "s", "p", "d", and "f" orbitals are used to hold electrons. The "s" orbital holds two electrons, the "p" holds 6, the "d" holds 10, and the "f" holds "14". If you look at the periodic table, the first two rows of elements only have "s" and "p" orbitals. The "d" orbital comes in when you start the 4th row of the periodic table. ALl the elements in that middle block have "d" orbitals. All the elements in the block at the bottom (the one that is spliced out of the periodic table and seen at the bottom in two rows) have "f" orbitals. What do you need to know about these for an O. Chem test? Just what everybody else said before, that the blending of the "s" and "p" orbitals help to make up an sp3 hydrization. I tutored o. chem for two years.... and the main question that the professors asked every quarter in regards to hybridization is simply to be able to identify if something is sp3, sp2, or sp hybridized. If you can do that, you'll do fine! Good luck!

 

[dr.day]

kidsmd,
thanks so much! that is exactly what I needed to hear!
I appreciate it!

 

[solid snake]

Also, you need to keep into account lone pairs. For example, with NH3, N is bonded to 3 atoms, but it has sp3 orbitals. On the N atom, their is one lone pair, so 3 atoms + lone pair=sp3 orbitals.
You can think of the lone pair as a "bond" and count it.

 

[CD]

While it probably won't matter for the first test, you might want to remember the SHAPE of those orbitals. It can matter in determining reactions later on.

ei: s orbitals are spherical and the electron density is at the nucleus, while p orbitals are dumbell shaped and there is a nodal plane at the nucleus so electron density is some distance from the nucleus. Therefore electrons in a p orbital aren't held as closely and are more availiable for use in reactions. That's why when you have a sp2 orbital (which leaves 1 p orbital unhybridized) the sp2 orbitals are less likely to be used in a reaction....it has more s character. While the remaining p orbital is completely p in character and is quick to react.

 

[dr.day]

I greatly appreciate all the help. Do you all find this hard to grasp w/o being able to actually see or touch it? I have a hard time conceptualizing things like this. What advice do you have for studying for this class? I don't feel like our text is very helpfull so if you know of a good study guide please let me know. Luckily our prof is cool, but unfortunately she can't be with me all the time ....well, actually, I am glad she isn't here ALL the time!

 

[Cobragirl]

Organic...uggh....I'll take pathology any day!