Valence Bond Theory: Hybridization

How would an s orbital combine with a p orbital to form a covalent bond? The answer is through hybridization where a hydribid oribital is formed. 

Atomic Orbitals vs. Hybrid Orbitals

Concept: Understanding Overlapping Atomic Orbitals 

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Video Transcript

What we should realize is that covalent bonds are formed when atomic orbitals basically just overlap with their electrons. Now for electrons to overlap, they have to be in the same type of orbital. So an s orbitals has to overlap with an s orbital. A p orbital has to overlap with a p orbital.
So if we take a look at this first example, here we have two Hydrogens. They want to combine to give us H2. Now, their electron configurations are 1s1. So they each have 1 electron in their first shell. Now, they can overlap to form a bond, because here, what’s going to be forming the bond are their s orbitals. Each s orbital needs one more electron in order to get to 1s2, so that each Hydrogen can be just like Helium. Now, again since they are both s, they can overlap. So that’s what they do. And the electrons are in here. And in this way they get to share the electron of the other Hydrogen, and that way they have two electrons around them, and they are satisfied.
Now if we take a look at two Chlorines, they can also overlap their p orbitals, because the electron configurations will be Argon, or actually [Ne]3s23p5, [Ne]3s23p5. Remember, chlorines want to gain one more electron to become just like Argon. Where can that one electron go? It’s going to go to the p orbitals, because remember, p can hold up to 6 electrons. So there’s an electron in here, and there’s an electron in here. And they are going to overlap with one another, so that they can share those electrons.
So here we’re going to say is where they form their bond. We’re going to say this is a direct overlapping of their atomic orbitals, we say that this is called a sigma bond. A sigma bond is a direct overlapping of atomic orbitals. They share electrons with each other in order to complete their octet, to be just like closest noble gas. 

A sigma bond is formed by the direct end to end overlapping of atomic orbitals. 

Concept: Understanding Hybrid Orbitals 

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Video Transcript

Now, we’re going to say that the opposite of a sigma bond is a pi bond. We’re going to say a pi bond is a sideways overlapping of p orbitals. And we’re going to say if you have elements single bonded to each other, you have 1 sigma. Every bond you make is always a sigma bond.
C-C
Let’s say compound has two bonds together. It’s a double bond. Well, it’s going to have 1 sigma, and 1 pi.
C=C
And let’s say compound has three bonds, triple bonds. Again, it’s going to have 1 sigma, and 2 pi bonds. Every extra bond you add, that’s what pi bond be added.
C=C
So just remember, here we’re talking about direct overlapping of atomic orbitals, so we’re talking about the formation of a bond. A sigma bond. And then we’re going to say if we have a double bond or a triple bond, those will be pi bonds that we’re adding on top of the sigma bond. They are kind of like bread that goes around the meat of the bun. The meat portion will be the sigma bond, bread part adds extra strength to that sigma bond.
Now, what would happen though if we’re trying to form a covalent bond with different atomic orbitals?
For example, we have BeCl2. Now BeCl2 looks like this.
Cl-Be-Cl
Looks like Beryllium is in group 2A, so there are two bound electrons, Chlorine is in group 7A, so it has seven. Halogens are not in the center, only make one bond. But the problem here is, electron configuration of Beryllium is Helium, 2s2, and Chlorine is [Ne]3s23p5. And here’s the thing. An s and a p cannot mix together. There are different atomic orbitals. They have to both be the same letter for them to successfully mix. This is where hybridization comes into play. Now, hybridization is a way of us mixing our s, our p, and sometimes our d orbitals together, to make hybrid orbital. That hybrid orbital will have a little bit of s character, p character, and d character. That will allow the central element to form bonds with basically any other element.
So what’s going to happen here is, for the Beryllium to form a bond with the Chlorine, it needs to somehow gain a p orbital. So what’s going to wind up happening here is, in this 2s electron orbital, we’re going to have a promotion of one of its electrons. So this electron here is actually going to get promoted, and jump up to the 2p orbital. And as a result, we have now one in the 2s, one in the 2p.
And we’re going to say here, now the way it looks visually is this. And I’m going to move myself away from shock guide so we have more room to write stuff. So visually this is the way it looks. We have our electrons in the 2s, remember the shape of s is a sphere. We want to promote it to the p, and p looks like a dumbbell. Like that. What’s going to happen like I said is this electron is going to jump over here, and what that really means is that this p and this s shape are going to mix together, and they are kind of going to spit out a hybrid baby. This hybrid orbital is going to have a little s character, a little bit of p character. And as you can notice, it kind of looks like a dumbbell but one side is a lot bigger than the other side. It’s a hybrid of these two guys here. These are the parents, and this is their offspring. And because we promoted one electron to the two p region, we’re going to say that this becomes an sp hybrid orbital. Because it has one that’s in the s, and one that went to the p. That’s why it’s called sp. But remember. p has how many electron orbitals? p has three electron orbitals. We only had enough electron to place only one of them, so these two over here are not being utilized. We’re going to say those two over here, those two electron orbitals are called unhybridized orbitals.
This is the way bonds form, and if the atomic orbitals are different letters, they cannot mix together. So to get around this, we’re going to mix up those orbitals together, forming hybrid orbitals. Since this now has s and p characteristics, it can form a bond, with Chlorine. Because Chlorine wants something with p characteristics involved. Since it is hybrid, it does have p characteristics involved so that’s why we were able to do this. Now hybridization is a little conceptual, really conceptual, but just remember the basics of this. When it comes to answering questions, which we’re going to do next, it’s really easy and simple to follow, as long as you look at it in a very simple way. So just get down to the fundamentals of this. In order for different atomic orbitals, different letters to connect together, we have to mix and hybridize the atomic orbitals of the central element. And in that way we can form bonds. 

For an s orbital to bond with a p orbital the central element must first undergo hybridization. 

Determining Hybridization

Concept: Simplifying Hybridization 

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Video Transcript

The conceptual part of hybridization is a little bit confusing and weird, but the good thing is when you're asked questions, you're not going to be writing essays on it. Yours is going to be answering questions dealing with hybridization, so we're going to look at it in a very simple way and it's based up of the electronic geometry.
We're going to say here, your hybridization of your central element is sp when your central element is connected to two groups. Remember when you're connected to two groups, your electric sees AX2. If you're AX2, you're linear. If your hybridization is sp2, then your central element is connected to three groups. If it's sp3 it's four groups, sp3d—five groups, sp3d2 six groups.
The simplest way to think of it is like this, 'There's a power here that we don't see. One plus one gives us two, two groups.' There's a one here that we don't see, one plus two gives us three, three groups. One plus three gives us four, one plus three, plus one gives us five. One plus three plus two gives us six. Simplest way to look at it! It's keeping a lot of the theory involved with promotion of the electron to the next available atomic orbital. We're just basically breaking it down and connecting it directly to electronic geometry.
Let's take a look at the first example and you'll see how easy it really is. 

To determine the hybridization of a central element we look at the number of groups around it. 

Example: For each of the given covalent compounds draw out the Lewis Structure and answer the questions.  

CH2Cl2                        Hybridization:                                                                    

                                     Unhybridized Orbitals:                                                                                                                                        Bonding orbitals (C – H):

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Example: For each of the given covalent compounds draw out the Lewis Structure and answer the questions.  

XeCl5+                        Hybridization:                                                                    

                                     Unhybridized Orbitals:                                                                                                                                        Bonding orbitals (Xe – Cl):

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Problem: For the given covalent compound draw out the Lewis Structure and answer the questions.

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Problem: For the given covalent compound draw out the Lewis Structure and answer the questions.

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Valence Bond Theory: Hybridization Additional Practice Problems

What is the hybridization of the central atom of each of the following molecules? Match the atoms below with their number---sp, sp2, sp3, sp3d, sp3d2

COH2

H2S

PBr5

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How many nitrogens are sp3 hybridized?

  1. 5
  2. 3
  3. 2
  4. 1
  5. 0
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N,N-diethyl-m-tolumide (DEET) is the active ingredient in many mosquito repellents. What is the hybridization state of the atoms indicated by the arrows in the structure of DEET shown below.

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If you assume sphybridization for a free nitrogen atom, how many lone pairs of electrons will the free (not bonded to other atoms) nitrogen atom have?

a. 0

b. 1

c. 2

d. 3

e. 4

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Consider the compound ethene, C2H4. The bond between the two carbons that is formed above and below the internuclear axis is a     ?      bond. The atomic orbitals that combine to form this bond are      ?      orbitals.

1. σ ; sp3

2. π ; sp2

3. π ; 2p

4. π ; 1p

5. σ ; sp2

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What is the hybridization of carbon in CH 2O? C is the central atom.

1. sp3d

2. sp3

3. sp

4. sp2

5. sp3d2

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Consider the line formula for the migraine medication, Imitrex.

What is the correct empirical formula for this compound?

1. C14H21N3O2S
2. C14H19N3O2S
3. C13H20N3O2S
4. C12H20N3O2S
5. C12H21N3O2S
6. C13H19N3O2S

Which of the following best represents the bond angle labeled a?

1. 90°
2. 118°
3. 178°
4. 120°
5. 107°
6. 109.5°
7. 180°

What is the hybridization of the atom that is labeled b?

1. sp2
2. sp3
3. sp3d2
4. sp3d
5. sp

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If a molecule has square planar molecular geometry, what must be its hybridization?

1. sp2

2. sp3d

3. sp3

4. sp32

5. sp

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Which of the following  molecular geometries would have an sp3 hybrid orbital structure?

a. linear

b. t-shaped

c. bent

d. triangular planar

e. square pyramid

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Give the hybridization for the O in OCl 2, assume that O is the central atom.

A. sp

B. sp2

C. sp3

D. sp3d

E. sp3d2

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Which of the following describes sp 2 hybridzation?

A. Three orbitals are hybridized, one p-orbital remains unhybridized

B. Three orbitals are hybridized, one s-orbital remains unhybridized

C. Three orbitals are hybridized, no orbitals remain unhybridized

D. Four orbitals are hybridized, no orbitals remain unhybridized

E. Four orbitals are hybridized, one s-orbital remains unhybridized

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Which image below is the correct depiction of the hybridized orbital for a carbon in a molecule of formaldehyde (CH2O)?

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(A) Complete the following table. 

Hybrid type                      Geometry of electron pairs 

a  ___________                linear 

b     sp3                           _________ 

c  ___________                trigonal bipyramidal 

d  ___________                octahedral 

e      sp2                          __________

 

 

 

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N,N-diethyl-m-tolumide (DEET) is the active ingredient in many mosquito repellents. What is the hybridization state of carbon indicated by the arrow in the structure of DEET shown below?

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Indicate the type of hybrid orbitals used by the central atom in PCl 3

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Determine the hybridization for the central element of each compound given below.

(a) SO42−

(b) CH4

(c) SF6

(d) PCl5

(e) H2O

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In the molecule below, how many of the atoms have sp 3 hybridization?

(a) 1

(b) 2

(c) 3

(d) 4

(e) 5

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One product of the combustion of methane is carbon dioxide. What change in hybridization of the carbon occurs in this reaction?

 

a) sp to sp3

b) sp2 to sp

c) sp2 to sp3

d) sp3 to sp

e) sp3 to sp2

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Consider the hybridizations at the four different carbons in the molecule. The bond between C2 and C3 can be described as between orbitals:

a) sp hybrid on C2 and sp2 hybrid on C3

b) sp2 hybrid on C2 and sp2 hyrid on C3

c) sp3 hybrid on C2 and sp3 hybrid on C3

d) unhybridized p on C2 and unhybridized p on C3

e) sp hyrid on C2 and sp hybrid on C3

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In which one of the following molecules is the central atom sp 2 hybridized?

            A)  SO2    B)  N2O    C)  BeCl2    D)  NF3    E)  PF5

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A molecule has two lone non-bonded pairs of electrons on the central atom and four atoms bonded to the central atom. What is its molecular shape and its hybridization?

1. octahedral; sp3d

2. pyramidal; sp3

3. square pyramidal; sp3d2

4. tetrahedral; sp3d2

5. square planar; sp3d2

6. tetrahedral; sp3

7. square planr; sp3

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A molecule has one lone pair of electrons on the central atom and three atoms bonded to the central atom. The central atom follows the octet rule. What is its electronic arrangement and its hybridization?

1. tetrahedral; sp3

2. tetrahedral; sp2

3. trigonal planar; sp3

4. angular; sp3

5. trigonal planar; sp2

6. pyramidal; sp3

7. pyramidal; sp

 

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What hybridization would you expect for the carbon atoms in the cyclic compound benzene (C6H6)?

1. sp3d

2. sp3d2

3. sp3

4. sp2

5. sp

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The C-C pi bond in ethylene H 2CCH2 results from the overlap of which orbitals?

a. Two sp3 hybrid orbitals, one on each C atom

b. Two 2p atomic orbitals, one from each C atom

c. Two 2s atomic orbital, on each C

d. Two sp hybrid orbitals, one each C

e. Two sp2 hybrid orbitals, one on each C

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What type of hybridization is exhibited by the central atom in CH 2O?

a. sp2

b. sp

c. sp3

d. sp3d

e. sp3d2

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What types of orbitals overlap to form each C-H sigma bond in methane CH 4?

A. C-sp3 and H-1s

B. C-2s and H-1s

C. C-sp and H-2s

D. C-sp and H-1s

E. C-sp2 and H-1s 

 

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What is the hybridization of the oxygen atom labeled x in the structure below?

a. sp

b. sp2

c. sp3

d. sp3d

e. sp3d2

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The central atom in ICl2  uses which kind of hybrid orbitals?

1. sp         2. sp 2          3. sp 3          4. sp 3d          5. sp 32

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A central atom in a species with a square planar molecular geometry use this typical hybrid orbital.

1. sp         2. sp 2         3. sp 3         4. sp 3d         5. sp 3d2

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The orbital or orbitals shown below is or are most correctly described by which of the following answers?

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What hybrid orbitals are used for bonding by the central atom N in NOF3? (N is the central atom)

1. sp

2. sp2

3. sp3

4. sp3d

5. sp3d2

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ICl3 is sp3 d hybridized. What is the electronic and molecular geometry?

1. tetrahedral; pyramidal

2. trigonal bipyramidal; T-shaped

3. trigonal planar; trigonal planar

4. octahedral; T-shaped

5. trigonal bipyramidal, seesaw

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