I was asked to prepare a funny and accurate article on orbital hybridization. Here it is! Please let me know what you think!!
A carbon atom went to visit a Chemist. “Doc.” it said, “I have issues. I so want eight electrons to hang with me. But whenever I find some they don’t want to stay with me. The electrons tell me they are to close together.”
“That is interesting. Could you tell me what your ground state configuration is?” asked the Chemist.
“ 1s2 2s2 1pz1 1py1” replied Carbon.
“Could you draw a picture of that?” The chemist continued.
“Ah, sure…”
| C* | ↓↑ | ↓↑ | ↑ | ↑ | __ |
| 1s1 | 2s | 2p | 2p | 2p |
Figure 1: Carbon, ground state electron configuration
The Chemist paused and reviewed the drawing. “So,” the Chemist asked, “If I am reviewing this correctly, this is a representation of your electrons in their ground state, the lowest energy state. The valence electrons are 2s and 2p. Two electrons fully occupy the 2s orbital and of the three p-orbitals, two of them contain 1 electron each. Is that correct?”
“Yes” answered Carbon.
“Electrons are little negative charges. Each pair would prefer to be as far apart from a neighboring pair as possible. If you have 4 pairs if electrons, for a total of eight electrons, do you know the angle between each fully occupied orbital?”
“No” said Carbon.
“Neither do I!” said the Chemist, “But I think you can maximize the orbital distance if you hybridize your s– and p-orbitals. Let me draw a picture for you.” Scribble, scribble…scribble. The Chemist drew this picture.
| C* | ↓↑ | ↑ | ↑ | ↑ | ↑ |
| 1s1 | sp3 | sp3 | sp3 | sp3 |
Figure 2: Carbon, sp3 electron configuration
“Mix all the s– and p-orbitals into four hybridized orbitals. Each is ¼ — s and ¾ — p, in other words, 25% s and 75% p. That makes all the orbitals identical. In total, the four hybridized sp3–orbitals have slightly more energy than the ground state configuration. This orbital geometry is called ‘tetrahedral’. Each orbital is 109.5° apart from the other the maximum distance the orbitals can be.”
“Cool.” said Carbon, “I’ll bet that with hybrid orbitals, the bonds made with the four electrons I want would be satisfied. I’m going to make four C-H single bonds!!!” With that Carbon left.
The next day Carbon returned with four brand new C-H bonds. “Hey, check me out, I’m a methane now.”
Methane
Figure 3: Tetrahedral Structure of Methane.
The Chemist agreed Methane was very cool. The Chemist continued, “There is more to hybridization than sp3 hybrid orbitals. When a carbon wants to form a double bond, an sp2 hybrid is made. In ethene, the single bonds (σ-bonds) are made when sp2 orbitals overlap the other bond of the double bond, the π (pi) bond is not hybridized. The other bond of the double bond is a π (pi) bond. Here, look at these pictures of ethene.”
Figure 4: Structure of Ethene
“An ethene carbon has two single bonds (σ-bonds) and one double (π , pi) bond. The single bonds are sp3 orbitals, in the double bond, one bond is sp3 the other is p. Here is another picture. Check out the σ-bonds and π-bond. Orbital (bond angles) are maximized at 120oC
Figure 5: Orbital Diagram of Ethene1
“The electron sp2 hybrid diagram of that carbon is this.”
| C* | ↓↑ | ↑ | ↑ | ↑ | ↑ |
| 1s1 | sp2 | sp2 | sp2 | p |
Figure 6: Carbon, sp2 Electron Configuration
“And there is one more; the sp hybrid. That is used when a carbon needs a triple bond, like in acetylene. The sp hybridization diagram is…”
| C* | ↓↑ | ↑ | ↑ | ↑ | ↑ |
| 1s1 | sp | sp | p | p |
Figure 7: Carbon, sp Electron Configuration
The 2 the π-bonds are not hybridized, but the two σ-bonds (single bonds) are. Here is picture of the bonds of acetylene. Orbital (bond angles) are maximized at 180°!”
Figure 8: Orbital Diagram for Acetylene2
“SWEET!” Carbon said after the Chemist finished his explanation. “This hybridization stuff is really cool. I can make so many excellent molecules with the different hybridization states.” With that Carbon (now Methane) went out into the world to make an many new bonds.
© Gloria A. Rood 2011
© Grove Ridge Consulting, 2011