Molecular vs Electron Geometry

Whenever we draw a molecule we must take into account two different systems of geometrical shape. 

Electronic Geometry

Concept: Understanding Electronic Geometry 

4m
Video Transcript

We've said that when we’re describing the shape or geometry of a compound, there were two systems that we use. There's electronic geometry and there's molecular geometry. This first one that we're going to look at is the electronic geometry. We're going to say that this one is known as the simpler geometry.
Electronic geometry can also be called orbital shape. What we need to realize about the electron geometry is it doesn't discriminate. It treats lone pairs and the surrounding elements around my central element as the same. Lone pairs and surrounding elements are both treated as X. We're going to say our central element is A. Using this system to identify different groups in your structure will make it an easier way for you to memorize the different names associated with this structure.
If we take a look at this compound, this made-up compound, we have AX3. A is our central element. We're going to say A. We're going to say it has three surrounding elements around it and it also has a lone pair. We’re going to treat the lone pair and the surrounding elements as the same. We're going to have AX4. AX4 would be the electronic geometry of this compound. All you’d have to do is come down here and realize if you’re AX4, then your electronic geometry is tetrahedral. You’re AX4 because you're surrounded by four different groups. Your central element is surrounded by four different groups. These different groups can be in different arrangements.
Let's go through each of these. If you're AX2, that means your central element is surrounded by two groups. Again, those groups could be a lone pair and a surrounding element or two surrounding elements. Here, carbon is our central element A and it’s surrounded by two of these surrounding elements. Here, central element is carbon and it's surrounded by two elements. If you're AX2, your electronic geometry is linear.
AX3, this would mean that your central element is connected to three groups. Here we have boron which is A, our central element, and it’s surrounded by three surrounding elements so it’s AX3. SnF2, Sn is the central element A. It's surrounded by two surrounding elements and a lone pair. Remember, we treat surrounding elements and lone pairs as the same. We treat them both as X. We have three groups, so AX3. Here, nitrogen is surrounded by a lone pair and three surrounding elements, AX4. Carbon here will be AX4.
Here if you’re AX5, your electronic geometry is trigonal bipyramidal. Here, xenon is in the center. It’s surrounded by two surrounding elements but it also has three lone pairs. We treat all those groups as X, AX5. Phosphorus here would also be AX5. Here, xenon would be our central element A. It’s surrounded by four elements and has two lone pairs, AX6. Sulfur, AX6.
What I want you guys to realize is remember, electronic geometry doesn't see a difference between lone pairs around the central element and surrounding elements. It treats them as the same. As long as you can remember the AX system of labeling things, then it becomes that much easier.

The electronic geometry of a compound treats surrounding elements and lone pairs on the central element as the same.

Example: Draw each of the following compounds and determine their electronic geometries.

PH3

2m

Example: Draw each of the following compounds and determine their electronic geometries.

BeCl2

2m

Problem: Draw the following compound and determine its electronic geometry. SBr4

3m

Problem: Draw the following compound and determine its electronic geometry. IF3

2m

Problem: Draw the following compound and determine its electronic geometry. H2S

2m

Problem: Draw the following compound and determine its electronic geometry. PO3 -

2m

Molecular Geometry

Concept: Understanding Molecular Geometry 

6m
Video Transcript

We’ve said that there are two ways of looking at the shape of the structure, there is the electronic geometry and now there is the molecular geometry. The molecular geometry is the more complex way of looking at it, but the thing is it’s the more accurate way of describing what’s happening.
Now we’re going to say that molecular geometry treats lone pairs and surrounding elements as different. So remember here is the key, our central element is A, the surrounding elements around that central element are X, and then the lone pairs on the central element are E.
So if we look at this made up compound AX3 up top with the lone pair, we’d say that A is the central element, it’s connected to three surrounding elements and it has one lone pair on the central element, so that would be E1. Now technically, it around four groups so we go here to the four group section and we look, AX3E1 will be classified as trigonal pyramidal.
So there’s a lot more shapes to remember now because of this, but, again, remember the molecular geometry is the more accurate way of describing the shape because what we should realize these lone pairs think of them as a raging fire or something that is out of control. Something like that would need a lot of room for itself.
What’s happening here is because of we have these non-bonding electrons they’re going to need as much room as possible because they’re just pure energy, so what they do is they push away the other guys. They compress the bonds of those other guys, so the lone pairs are more towards self on one end of the compound; this causes us to have a different shape. The molecular geometry is a great way of explaining how that shape looks. Pyramidal, you can see that this here kind of looks like a pyramid, so that’s why they call it trigonal pyramidal.
Now if you go to this, if you have two groups, here this is AX2, there’s no lone pairs around the central element, same thing here. For three groups you could be AX3 where you have no lone pairs or AX2E1. Here Sn is in the center. It has two surrounding elements so that will be the X and it has one lone pair so that would be E1. This shape can come in three different names. They all mean the same thing, so be careful your professor could say bent, angular or V shape. Every single one means the same exact thing.
If we have four groups around the central element, we could have AX4 where it has no lone pairs, we could have AX3E1 or we could have AX2E2. And, again, AX2E2 is just like AX2E1, it would be classified as bent, angular or V shape.
If you have five groups around your central element, then it goes really crazy with the number of shapes that you could have. Here AX5 would mean that the central element has no lone pairs around it. AX4E1 will be seen as seesaw. And another way we could have drawn this is we could have drawn a seesaw like this. You may see it like that as well. AX3E2 is T-shaped and you can see that this looks like a T, that’s why they call it T-shaped. Here AX2E3 is actually linear, it’s just like the AX2 up here; it’s linear as well. All the lone pairs decide to orient themselves in this way kind of forming like a triangle and then the surrounding elements are on either side.
Then if your AX6, well if you have six groups it can be AX6 or you’re octahedral. If you have one lone pair your AX4E1 and your name is square pyramidal. And then you could be AX4E2 and there you’ll be square planar kind of shaped like a square.
So, again, the molecular geometry, even though it’s more of a pain, it’s a more accurate way of describing the real shape of these compounds. They’re basically telling us how do the lone pairs influence the shape of our molecular compound.
The lone pairs are like pure energy, they’re pushing all the other bonds away from them. This actually gives them weird-looking shapes where the names come into play. So there’s more memorizing here than with electronic geometry but if you can memorize this entire page, it will be just like memorizing electronic geometry because we know electronic geometry AX2 is linear, AX3 is trigonal planar, AX4 is tetrahedral, AX5 is trigonal bipyramidal and AX6 is octahedral.
I would recommend just memorizing this page here because that way you can take out molecular geometry and electronic geometry all at the same time. But remember there’s a distinction, electronic geometry treats lone pairs and surrounding elements as the same, as just X, molecular treats them as different. We have X for surrounding elements and we have E for lone pairs.

The molecular geometry of a compound treats surrounding elements and lone pairs on the central as different. 

Example: Draw each of the following compounds and determine their molecular geometries. 

PH2   

2m

Example: Draw each of the following compounds and determine their   molecular geometries. 

XeCl2

2m

Problem: Draw the following compound and determine its molecular geometry. OBr2

2m

Problem: Draw the following compound and determine its molecular geometry. SO 2 -

2m

Molecular vs Electron Geometry Additional Practice Problems

The shape of the carbon dioxide molecule is

a. tetrahedral 

b. triangular 

c. pyramidal 

d. linear

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A 0.02847 g sample of gas occupies 10.0-mL at 292.0 K and 1.10 atm. Upon further analysis, the compound is found to be 38.734% C and 61.266% F. What is the molecular formula of the compound? 

Draw the Lewis structure of the compound. 

Identify the geometry around each carbon atom.

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Consider the following molecular shapes:

(a) Which has the most electron pairs (both shared and unshared) around the central atom? 

(b) Which has the most unshared pairs around the central atom? 

(c) Do any have only shared pairs around the central atom?

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Name all the molecular shapes that have a tetrahedral electron-group arrangement.

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Which of the following numbers of electron groups can give rise to a bent (V-shaped) molecule: two, three, four, five, six? Draw an example for each case, showing the shape classification (AXmEn) and the ideal bond angle.

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In what situation is the name of the molecular shape the same as the name of the electron-group arrangement?

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If you know the formula of a molecule or ion, what is the first step in predicting its shape?

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a. What is the molecular geometry of PF3? Enter the molecular geometry of the molecule.

b. What is the molecular geometry of BeF2? Enter the molecular geometry of the molecule.

c. What is the molecular geometry of OF2? Enter the molecular geometry of the molecule.

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a. Draw the electron-dot structure for CHClO. Draw the molecule by placing the atoms on the grid and connecting them with bonds. Include all lone pairs of electrons.

b. What is the electron-domain (charge-cloud) geometry of ClF5? Enter the electron-domain geometry of the molecule.

c. What is the molecular geometry of ClF5? Enter the molecular geometry of the molecule.

d. ignoring lone-pair effects, what is the smallest bond angle in ClF5? Express your answer as an integer.

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a. What is the electron-domain (charge-cloud) geometry of IF5? Enter the electron-domain geometry of the molecule.

b. What is the molecular geometry of IF5Enter the molecular geometry of the molecule.

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What is the molecular geometry of the bromate ion, BrO3?

a. square planar
b. trigonal planar
c. square pyramidal
d. tetrahedral
e. trigonal pyramidal

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Which of the following characteristics does not apply to PF3?

a.contains polar bonds
b.has three σ bonds
d.trigonal planar
d.one lone pair of electrons on phosphorus
e. polar molecule

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Determine the molecular geometry of SCl 6.

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Determine the molecular geometry of ClF4-.

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What is the electronic geometry of SCl4? Enter the electronic geometry of the molecule.

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What is the electron-domain (charge-cloud)geometry of BrF5?

What is the molecular geometry of BrF5?

Ignoring lone pair effects, what is the smallest bond angle in BrF5?

Express your answer as an integer

What is the hybridization about the central atom in BrF5?

Express your answer in analogy to the following example: sp2.

Which choice best describes the polarity of BrF5?

 

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Molecular geometry of IF2-1 and lewis structure?

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What shape would you expect for XeF4?


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Draw the Lewis structure of H2O. Include any nonbonding electron pairs. Include all lone pairs of electrons.


What is the electronic geometry of H2O?


What is the electronic geometry of ClF3?


What is the electronic geometry of BBr3?

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Match each two-dimensional structure to its correct three-dimensional description. Drag the appropriate items to their respective bins.

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a. What is the molecular geometry of BrI 5




b. Ignoring lone-pair effects, what is the smallest bond angle in BrI 5? (Express your answer as an integer).

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What is the molecular geometry of H3O+, hydronium ion?

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a. Predict the molecular geometry of ClNO.

b. Enter the molecular geometry of ClNO.

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What is the electron-domain (charge-cloud) geometry of BrI 5?

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Which of the following molecules is not planar?

a. NCCN

b. H2CCH2

c. SO3

d. SeF4

e. XeF2Cl2

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What is the electron-domain (charge-cloud) geometry of BrF5?

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Predict the molecular shape of methane, the carbonate ion, carbon dioxide, and the sulfite ion.

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Consider the following molecules

i) BrF3, ii) SO42-, iii) ClO2, and iv) SO2,

A) Draw ONE appropriate Lewis structure for each of the four chemical species listed above.

B) What are the electron domain geometries surrounding the central atoms?

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What is the electron geometry of NF 3?

 

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The molecular geometry of the CH 3+ ion is best described as _______________ .

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Determine the molecular geometry, or shape, of ClO 2

A) octahedral

B) tetrahedral

C) trigonal bipyramidal

D) trigonal planar

E) t-shaped

F) bent

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a) Select all of the equatorial atoms on the structure below. You may need to rotate the molecule to see all the atoms.

b) What is the shape of this molecule?

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a) Select all of the equatorial atoms on the structure below. 

b) What is the shape of this molecule?

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a) Select all of the equatorial atoms on the structure below.

b) What is the shape of this molecule?

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Determine the Electron geometry, molecular geometry, idealized bond angles for each molecule.

PF3, SBr2, CHCl3, CS2

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According to VSEPR theory, the geometry of the PH 3 molecule is best described as: linear, trigonal planar, tetrahedral, bent, or trigonal pyramidal.

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What is the molecular geometry of a molecule with:

i) 4 outer atoms and 1 lone pair on the central atom?

ii) 2 outer atoms and 2 lone pairs on the central atom?

iii) 4 outer atoms and 2 lone pairs on the central atom?

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Draw the Lewis Structure for KrF2. The central atom has _____ lone pairs. It's geometry is ______.

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Part A: What is the molecular geometry of NF3?

Part B: What is the molecular geometry of HCN?

Part C: What is the molecular geometry of SCl2?

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What is the molecular shape of BrF 3 as predicted by the VSEPR theory?

A) Trigonal planar

B) Tetrahedral

C) Trigonal bipyramidal

D) T-shaped

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What is the electronic geometry of H 2O?

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Which of these molecules are linear? Check all that apply.

a) NO2-

b) XeF2

c) BeCl2

d) SF2

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1) Draw the lewis Dot Structures for CS 2 and SCl4
 

 

 

 

2) Using VSEPR rules, predict the geometry of the two molecules in question 1

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What is the electron pair geometry and Molecular geometry of SCl 2?

 

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What is the molecular shape of C2H2? What is the geometry of electron pairs around its central atom?

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The molecular geometry of the SF2 molecule is

a) linear.

b) bent.

c) trigonal planar.

d) tetrahedral.

e) octahedral.

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What is the molecular geometry of PCl 3?

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What is the molecular geometry of SF2?

a. Upside down

b. Bent

c. Tetrahedral

d. Linear

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The molecular geometry of NO2- is, Use VSEPR to justify your answer.

A) bent, bond angle - 109°

B) trigonal planar

C) linear

D) bent, bond angle - 120°

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What is the molecular Geometry of NO 2?

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Write down Lewis structure of ICl 3 and provide answer of its electron pair geometry, molecular geometry and hybridization of iodine.

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1. Draw the Lewis structure of the azide anion N  3-. Give its geometry. Is N3- polar (in the sense of having a non-zero electric dipole moment)?

 

 

2. Draw the Lewis structure of nitryl fluoride NO 2F (N is at the center). Give its geometry, including a discussion of the angles. Is NO2F polar?

 

 

 

3. Rationalize the following bond angles: NH 3 106.6°; NF3 102.2°; NCl3 106.8°.

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The molecular geometry of PF3 is best described as

A) trigonal planar

B) trigonal pyramidal

C) T-shapted

D) tetrahedral

E) the correct geometry is not listed

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What is the molecular geometry of NH 3?

a. Trigonal planar

b. Tetrahedral

c. Triangular pyramid

d. Bent

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Why does NO3- have a molecular geometry shape of trigonal planar?? Isn't it true that in order to be  trigonal planar there should be 4 bonded pairs and 0 lone pairs?

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What is the molecular shape of sulfur dioxide, SO 2, (i.e., what is the atom geometry around the central atom)?

A) linear

B) trigonal planar

C) bent

D) trigonal pyramidal

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Draw the Lewis structure for SeF4 and answer the following questions.

How many valence electrons are present in this compound?

How many bonding electrons are present in this compound?

How many lone pair (non-bonding) electrons are present in this compound?

Is SeF4 a polar or non-polar compound? 

What is the geometry of SeF4

What is the shape of SeF4

What are the approximate bond angles made by the atoms in this structure? 

Watch Solution

Draw the Lewis structure for CCl 4. What is the molecular geometry of this compound? Is the molecule polar or nonpolar?

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Which of these molecules are linear? Check all that apply.

a) XeF2

b) BeCl2

c) SF2

d) NO2-

 

Watch Solution

What shape would you expect for XeF4?

What are the expected bond angles in ICl 4+?

Check all that apply.

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What is the molecular geometry of ICl 4-?

  1. T-shaped
  2. Trigonal bipyramidal
  3. Seesaw
  4. Tetrahedral
  5. Square planar
Watch Solution

The predicted geometry of ICl3 would be

1. trigonal pyramidal.

2. linear.

3. trigonal bipyramidal.

4. T-shaped.

5. trigonal planar.

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The molecular geometry of ICl2 is

1. trigonal planar.

2. octahedral.

3. trigonal bipyramidal.

4. tetrahedral.

5. linear.

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Choose the correct description for SiOH 2. NOTE: Si is the CENTRAL atom and all the other atoms are attached to Si. 

1. polar, pyramidal

2. polar, trigonal planar

3. non-polar, T-shaped

4. polar, T-shaped

5. polar, tetrahedral

6. non-polar, pyramidal

7. non-polar, tetrahedral

8. non-polar, trigonal planar

Watch Solution

A molecule has four unshared electrons on the central atom and four chlorine atoms bonded to the central atom. What is its molecular shape and its hybridization?

1. square planar; sp3

2. pyramidal; sp3

3. octahedral; sp3d2

4. tetrahedral; sp3

5. square pyramidal; sp3d2

6. tetrahedral; sp3d2

7. square planar; sp3d2

Watch Solution

What is the molecular shape of the XeF 5ion?

1. tetrahedral

2. square pyramidal

3. trigonal bipyramidal

4. trigonal pyramidal

5. octahedral

Watch Solution

What is the molecular geometry around a central atom that is sp3d hybridized and has one lone pair of electrons?

 

Watch Solution

Which of the following is best described as T - shaped?

a) NH3

b) BCl3

c) XeF+ 

d) NO 

e) SO2−

Watch Solution

Select the correct molecular structure for SO 3 from the choices below:

a) T-shaped

b) trigonal planar

c) tetrahedral

d) octahedral

e) trigonal bipyramid

Watch Solution

What type of molecular structure does the XeOF 2 molecule have? (Xe is the central atom)

a) trigonal pyramidal

b) tetrahedral

c) T-shaped

d) trigonal planar

e) octahedral

Watch Solution

Which of the following is best described as T-shaped?

a) NH3

b) BCl3

c) XeF3+

d) NO3

e) SO32−

Watch Solution

Which of the following has a trigonal bipyramidal structure?

a) PCl5

b) IF5

c) NH3

d) I3

e) Two of these four molecules

Watch Solution

What type of molecular structure does the XeOF 2 molecule have? (Xe is the central atom)

a). trigonal pyramidal

b) tetrahedral

c) T-shaped

d) trigonal planar

e) octahedral

Watch Solution

Which of the following molecules has a nonlinear structure?

a) XeF2

b) BeCl2

c) SeO2

d) CO2

e) N2O (central atom is N)

Watch Solution

For the following molecules or ions, draw a VSEPR picture showing the approximate geometry and the positions of all bonded pairs and lone pairs. Also name the shape of the structure (considering only the position of the nuclei and not the lone pairs) and the hybridization scheme used by the central atom in its bonding.

Watch Solution

What is the VSEPR geometry for CIO3-? _________________
What is the molecular geometry = shape of CIO3-? ___________________
Is CIO3- a polar or non-polar ion? ______________
What is the approximate O-Cl-O bond angle in CIO3-? ______________

Watch Solution

Classify these structures according to their molecular geometry = shape. You can use the answers more than once.

___ XY5            A. octahedral
___ XY3Z2        B. bent (~120°) 
___ XY2Z3        C. trigonal bipyramidal
___ XY2Z2        D. square pyramidal
___ XY4Z2        E. trigonal pyramidal
                        F. square planar
                        G. linear
                        H. bent (~109.5°)
                         I. T-shaped
                        J. trigonal planar
                        K. tetrahedral

Watch Solution

Classify these structures according to their valence shell electron pair repulsion geometry. You can use the answers more than once.

____ XY2                           A. octahedral
____ XY2Z                         B. trigonal bipyramidal
____ XY3Z2                       C. tetrahedal
____ XY2Z2                       D. linear
                                         E. trigonal planar

Watch Solution

Consider the polar chemical species XeO2Cl22-

.

A) Draw the Lewis electron dot diagram.

B) Draw a diagram, show and state the geometry around the central atom.

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Fill in the following table (see the ClF3 example). For the determination of formal charge(s) consider the Lewis formula with the smallest formal charges (lowest energy).

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The central atom of a molecule has three lone pairs and is bonded to each of two other atoms with a single bond. What is the molecular geometry (shape) of the molecule?

a) Linear

b) Trigonal planar

c) Trigonal bipyramidal

d) Octahedral

e) Square Planar

Watch Solution

The electronic arrangement is the same as the molecular shape when

A. the molecule is not polar.

B. the number of bonding orbitals equals the number of anti-bonding orbitals.

C. there are no lone pairs of electrons on the central atom.

D. the atoms are joined by sigma bonds.

E. there are more shared electrons than non-shared electrons.

Watch Solution

What are the electronic and molecular geometries of the molecule BrF 5?

1. octahedral, trigonal bipyramidal

2. trigonal bipyramidal, square pyramidal

3. ocahedral, square pyramidal

4. trigonal bipyramidal, trigonal bipyramdal

5. octahedral, octahedral

Watch Solution

Consider the polyatomic ion PCl 4- and its three dimensional structure. What is the electronic geometry and the molecular geometry for this ion?

1. tetrahedral; tetrahedral

2. trigonal bypyramidal; tetrahedral

3. octahedral; square planar

4. octahedral; square pyramidal

5. trigonal bipyramidal; T-shaped

6. trigonal bipyramidal; seesaw

Watch Solution

Consider a molecule of PCl5

Indicate whether the statements below are true or false.

 

Cl has a larger atomic radius than P.

When the preferred Lewis structure is drawn, no lone pairs appear on P.

PCl5 is a polar molecule.

Its molecular geometry is trigonal bipyramidal.

Its electron configuration is 1s22s22p63s23p64s23d104p65s24d2

Cl has higher first ionization energy than P.

The molecule has sp3 hybridization.

PCl5 is phosphorus pentachloride.

The bond between P and Cl is polar.

Watch Solution

 Give Lewis structures for the following molecules or ions.

a) HCFO 

 

 

 

b) CH3CH2OCH3

Watch Solution

When drawing a compound you have to take into account two different systems of geometrical shape.

  • With the MOLECULAR geometry you treat lone pairs (nonbonding electrons) and surrounding elements as different.

 

  • With the ELECTRONIC geometry you treat lone pairs (nonbonding electrons) and surrounding elements as the same. They are both treated as X.

 

Watch Solution

For which of the following compounds is the molecular geometry and electron geometry the same?

A. NBr3
B. ICI5
C. NH4+
D. BrF2-
E. XeF2

Watch Solution

How many of the following molecular are polar?

CF4             PCl  3            H 2S            ICl 5

a. 0

b. 1

c. 2

d. 3

e. 4

Watch Solution

What is the correct  electron geometry of SeF4?

a. tetrahedral

b. square pyramid

c. triangular bipyramid

d. see saw

e. t-shaped

Watch Solution

According to the VSEPR theory, the shape of the SO 3 molecule is

a. trigonal planar

b. pyramidal

c. square planar

d. tetrahedral

e. distorted tetrahedron (seesaw)

Watch Solution

Which is the best Lewis structure of the thiocyanate ion, SCN  ?

A) A

B) B

C) C

D) both A and C

E) A, B, and C are all equally plausible

Watch Solution

What is the molecular shape of the XeF5+ ion?

1. tetrahedral

2. square pyramidal 

3. trigonal bipyramidal

4. trigonal pyramidal

5. octahedral

Watch Solution

Draw out the Lewis Structure and answer the following questions. 

SF6                              

Number of Valence Electrons:

Molecular Geometry:

Electronic Geometry:

Hybridization:

Unhybridized Orbitals:

Polarity:

Bonding orbitals (S – F):

Intermolecular Force:

Watch Solution

Draw out the Lewis Structure and answer the following questions. 

SiBr42– 

Number of Valence Electrons:

Molecular Geometry:

Electronic Geometry: 

Hybridization:

Unhybridized Orbitals:

Polarity:

Bonding orbitals (Si – Br):

Intermolecular Force:

Watch Solution

Draw out the Lewis Structure and answer the following questions. 

C2H4

Number of Valence Electrons:

Molecular Geometry:

Electronic Geometry:

Hybridization:

Unhybridized Orbitals:

Polarity:

Bonding Orbitals (C – H):

Intermolecular Force:

Watch Solution

Draw out the Lewis Structure and answer the following questions. 

COCl2

Number of Valence Electrons:

Molecular Geometry:

Electronic Geometry:

Hybridization:

Unhybridized Orbitals:

Polarity:

Bonding Orbitals (C – O):

Intermolecular Force:

Watch Solution

Draw out the Lewis Structure and answer the following questions. 

NO2+

Number of Valence Electrons:

Molecular Geometry:

Electronic Geometry:

Hybridization:

Unhybridized Orbitals:

Polarity:

Watch Solution

Draw out the Lewis Structure and answer the following questions. 

IF2 

Number of Valence Electrons:

Molecular Geometry:

Electronic Geometry:

Hybridization:

Unhybridized Orbitals:

Polarity:

Bonding Orbitals (I – F):

Intermolecular Force:

Watch Solution

Draw out the Lewis Structure and answer the following questions. 

KrF5+

Number of Valence Electrons:

Molecular Geometry:

Electronic Geometry:

Hybridization:

Unhybridized Orbitals:

Polarity:

Watch Solution

The complete Lewis structure of the structure below will have

a) at least one lone pair on each atom.

b) at least one double bond.

c) both polar and nonpolar bonds.

d) resonance forms.

Watch Solution

What is the shape of the XeF4, molecule?

a) square planar

b) trigonal bipyramidal

c) tetrahedral

d) trigonal pyramidal

Watch Solution

Consider the given Lewis structure for BrF5. What is the predicted shape for the molecule as a whole?

a) square pyramidal

b) trigonal bipyramidal

c) trigonal pyramidal 

d) octahedral

Watch Solution

Which is linear?

a) H2S

b) NH3

c) NO2

d) CO2

Watch Solution

Which is planar?

a) NH3

b) SO32-

c) CO32-

d) CCl4

Watch Solution

In which pair are the molecules geometricaly similar?

a) SO2 and CO2

b) PH3 and BF3

c) CO2 and OF2

d) SO2 and O3

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The shape that most closely describes the NF3, molecule is

a) octahedral.

b) trigonal planar.

c) trigonal pyramidal.

d) tetrahedral.

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The molecule of the type ML4 consists of four single bonds and no lone pairs. What structure is it expected to assume?

A) square planar

B) trigonal planar

C) trigonal pyramidal

D) tetrahedral

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Which is an isomer of the structure that is given in the box below?

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Knowing that F is more electronegative than either B or P, what conclusion can be drawn from the fact that BF3 has no dipole moment, but PF3 does?

a) BF3 is not spherically symmetrical, but PF3 is.

b) The BF3 molecule must be trigonal planar.

c) The BF3 molecule must be linear. 

d) The atomic radius of P is larger than the atomic radius of B.

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Which compound would be expected to have the largest dipole moment?

a) CO2 (linear)

b) SO2 (bent)

c) BF3 (trigonal planar)

d) CF4 (tetrahedral)

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NH3 (pyramidal geometry) reacts with BF3 (planar geometry) to form the addition compound, H3NBF3. What is the geometry around the nitrogen and boron centers in the addition compound?

a) Both centers are tetrahedral.

b) Nitrogen is tetrahedral; boron is linear. 

c) Nitrogen is pyramidal; boron is planar.

d) Nitrogen is planar; boron is pyramidal. 

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For the molecule below, write the correct Lewis dot structure. Be sure to indicate any resonance structures, then draw the free dimensional structure based on VSEPR theory. Be sure to name the molecular structure, the geometry from which it is derived, and give the hybridization of the central atom(s).

SeF4

 

 

VSEPR structure:

Molecular structure:

Hybridization:

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Diborane, the simplest known member of the series of boron hydrides, is comprised of:

(a) 1 boron-boron bond, and 6 terminal hydrogens

(b) 1 BF3 ion and 1 BF3 + ion

(c) No boron-boron bond, 1 bridging hydrogen, 4 terminal hydrogens, and an ionic H

(d) No boron-boron bond, 2 bridging hydrogens and 4 terminal hydrogens

(e) No boron-boron bond, 4 bridging hydrogens and 2 terminal hydrogens

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Provide the following information for the generic dot structure given below. Be sure to use wedges for bonds coming out of the paper and dashed lines for bonds going into the plane of the paper and only show the lone pairs on the central atom.

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Provide the following information for the generic dot structure given below. Be sure to use wedges for bonds coming out of the paper and dashed lines for bonds going into the plane of the paper and only show the lone pairs on the central atom.

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Provide the following information for the generic dot structure given below. Be sure to use wedges for bonds coming out of the paper and dashed lines for bonds going into the plane of the paper and only show the lone pairs on the central atom.

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Provide the following information for the generic dot structure given below. Be sure to use wedges for bonds coming out of the paper and dashed lines for bonds going into the plane of the paper and only show the lone pairs on the central atom.

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Provide the following information for the molecule SeCl2O2. Be sure to assign all non-zero formal charges, use wedges for bonds coming out of the paper and dashed lines for bonds going into the plane of the paper, and only show the lone pairs on the central atom.

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Provide the following information for the molecule SeF3-. Be sure to assign all non-zero formal charges, use wedges for bonds coming out of the paper and dashed lines for bonds going into the plane of the paper, and only show the lone pairs on the central atom.

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Provide the following information for the molecule AsF3. Be sure to assign all non-zero formal charges, use wedges for bonds coming out of the paper and dashed lines for bonds going into the plane of the paper, and only show the lone pairs on the central atom.

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Provide the following information for the molecule SeO 2. Be sure to assign all non-zero formal charges, use wedges for bonds coming out of the paper and dashed lines for bonds going into the plane of the paper, and only show the lone pairs on the central atom.

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Provide the following information for the molecule BrF3. Be sure to assign all non-zero formal charges, use wedges for bonds coming out of the paper and dashed lines for bonds  going into the plane of the paper, and only show the lone pairs on the central atom.

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Dot structures are given below for several compounds containing iodine (lone pairs are shown only for the central atom). Draw the structure and name the molecular geometry from the following list: linear, bent, T-shaped, see-saw, trigonal pyramidal, trigonal planar, trigonal bipyramidal, square planar, square pyramidal, tetrahedral, octahedral. 

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Dot structures are given below for several compounds containing iodine (lone pairs are shown only for the central atom). Draw the structure and name the molecular geometry from the following list: linear, bent, T-shaped, see-saw, trigonal pyramidal, trigonal planar, trigonal bipyramidal, square planar, square pyramidal, tetrahedral, octahedral. 

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How would you describe the molecular polarity of SeCl 6?

  1. Nonpolar, because Se-Cl is a nonpolar bond and there is no lone pair on Se
  2. Nonpolar, because Se-Cl is a polar bond but the geometry is symmetric
  3. Polar, because Se-Cl is a polar bond although the geometry is symmetric
  4. Polar, because Se-Cl is a polar bond and there is a lone pair on Se
  5. Polar, because Se-Cl is a nonpolar bond but there is a lone pair on Se
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Identify the number of electron groups in XeF2

a.  2             b.  3                 c.  4                 d.  5                 e.  6

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Use VSEPR theory to predict the geometry of the PCl 3 molecule.

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Which one of the following Lewis structures is definitely incorrect? 

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Which is not a possible shape for molecules with trigonal bipyramidal electron group arrangements?

(a) Trigonal planar

(b) Linear

(c) See-saw

(d) T-shaped

(e) All the above shapes are possible.

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Phosphoryl iodide is used in the preparation of organophosphorus derivatives and phosphate esters. Select the best Lewis structure for POI3.

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Use VSEPR theory to predict the electron domain geometry of CS 2.

a) bent

b) linear

c) trigonal planar

d) tetrahedral

e) octahedral

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Give the number of valence electrons for cobalt (Co).

a.  18

b.  27

c.  2

d.  9

e.  7

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Which of the following compounds can exhibit cis-trans isomerism?

a) CH2=CH2

b) CH2Cl–CH2Br

c) CH2=CClBr

d) ClHC=CHCl

e) H2C=O

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What are the molecular geometries of the labeled carbon and nitrogen atoms in caffeine?

a) trigonal pyramidal and tetrahedral

b) trigonal pyramidal and trigonal planar

c) trigonal planar and tetrahedral

d) trigonal planar and trigonal pyramidal

e) Tetrahedral and tetrahedral

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What are the electron group geometries of the labeled carbon and oxygen atoms in aspartic acid?

a) trigonal pyramidal and bent

b) trigonal pyramidal and tetrahedral

c) trigonal planar and tetrahedral

d) tetrahedral and bent

e) trigonal planar and bent

Watch Solution

Which molecule does not contain a double bond?

a) HNO

b) C2H2

c) H2CO

d) C2H4

e) S2

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Predict the molecular geometry and polarity of the SO 2 molecule.

            A)      linear, polar                                           D)      bent, nonpolar

            B)      bent, polar                                             E)      None of the above.

            C)      linear, nonpolar           

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Which one of the following molecules has tetrahedral geometry?

 A)  XeF4         B)  BF 3         C)  AsF 5         D) NH 3          E)  CF 4

Watch Solution

For the molecule COCl2 write the possible Lewis Dot structures and indicate the correct one based on formal charge arguments. Show the formal charges for all elements in each structure and indicate how you arrived at them. If any resonance structures are possible Lewis structures, then they should be indicated. 

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Give the number of lone pairs around the central atom and the geometry of the ion SeO42–.

            A)      0 lone pairs, square planar

            B)      1 lone pair, square pyramidal

            C)      1 lone pair, distorted tetrahedron (seesaw)

            D)      0 lone pairs, tetrahedral

            E)      2 lone pairs, square planar

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The formaldehyde molecule, which has the formula CH 2O, has two possible structures for which we can write a correct Lewis dot structures.  Using formal charge, determine the correct structure.  Be sure to show how you compute the formal charge on each atom.

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The number of lone electron pairs in the N 2 molecule is ___.

A)  1   

B)  3   

C)  2   

D)  4   

E)  5

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Which of the following Lewis structures is incorrect?

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Determine the electron geometry (eg) and molecular geometry (mg) of BrF 3.

a) eg=trigonal planar, mg=trigonal planar

b) eg=trigonal bipyramidal, mg=T-shape

c) eg=trigonal planar, mg=bent

d) eg=trigonal bipyramidal. mg=see-saw

e) eg=tetrahedral, mg=trigonal pyramidal

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What is the molecular geometry around a central atom that has three bonding pairs and one lone electron-pair?

a) bent

b) linear

c) trigonal-planar

d) trigonal-pyramidal

e) trigonal-bipyramidal

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After drawing the Lewis structure determine what the molecular geometry of PCl 3 is 

a) trigonal bipyramidal

b) square planar

c) trigonal planar

d) V-shaped

e) trigonal pyramidal

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Provide one example of each of the following molecular geometries, provide the approximate bond angle around the central atom, determine the hybridization of the central atom, and comment on the molecule’s polarity.

             a. Tetrahedral

             b. T-shaped

             c. Square planar

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Provide one example of each of the following molecular geometries, provide the approximate bond angle around the central atom, determine the hybridization of the central atom, and comment on the molecule’s polarity.

 

a. Bent

b. Octahedral ion

c. Linear

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For the molecules below, provide the Lewis dot structure, draw the three dimensional dash-wedge structure, and comment on the polarity of the molecule.

a. Nitrous acid, HNO2

b. Polypropylene, CH3CHCH2

c. Percholorethylene, CCl2CCl2

d. Sulfonyl fluoride, SO2F2

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In which of the following molecules is the carbon-carbon bond likely to be the strongest?

a. H3CCH3

b. H2CCH2

c. CH3CH2F

d. HCCH

e. H2CO

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Which of the atoms listed below has a total of only four valence electrons?

(a) Beryllium

(b) Carbon

(c) Nitrogen

(d) Oxygen

(e) Fluorine

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What is the molecular geometry of SbCl 52- ? Antimony (Sb) can be an exception to the octet rule, accepting up to twelve electrons.

1. trigonal bipyramidal

2. square planar

3. square pyramidal

4. octahedral

5. seesaw

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What is the electronic geometry around nitrogen in the molecule CH 3CH2NH2?

1. square planar

2. trigonal planar

3. tetrahedral

4. bent

5. linear

6. trigonal pyramidal

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In the Lewis dot structure of the molecule ClF 3, how many unbonded electron pairs are found around the central atom?

1. 1

2. 3

3. 2

4. 0

5. 4

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White phosphorous is composed of molecules of P4 in which each P atom is connected to three other P atoms in the shape of a tetrahedron. Does it obey the octet rule?

1. No

2. Yes

3. Unable to determine

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Determine the electron geometry (eg), molecular geometry (mg), and hybridization of XeF4 .

A) Eg = tetrahedral, mg = tetrahedral, sp3 hybridization

B) Eg = linear, mg = linear, sp hybridization 

C) Eg = trigonal bipyramidal, mg = tetrahedral, sp3d hybridization

D) Eg = octahedral, mg = square planar, sp32 hybridization

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What is the expected molecular geometry of IBr 4 +?

a. see saw

b. trigonal planar

c. octahedral

d. tetrahedral

e. trigonal bipyramidal 

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What is the electron geometry and molecular geometry if a central atom has four total electron groups with two being bond pairs and two being lone pairs?

a. trigonal pyramidal , seesaw

b. tetrahedral , trigonal planar

c. tetrahedral , bent

d. trigonal planar, trigonal planar

e. trigonal pyramidal , linear 

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Why is it not recommended to draw double bonds between the Be atom and the Cl atoms in BeCl2?

a. It would give positive formal charges to the chlorine atoms and a negative formal charge to the beryllium atom

b. There would be too many valence shell electrons

c. It would result in more than eight electrons around beryllium

d. It would result in more than eight electrons around each chlorine atom

e. It would result in the formal charges not adding up to zero

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Which of the following is a possible valid Lewis structure for the compound which has the molecular formula C2H6O? 

a. 1 and 2

b. 2

c. 3

d. 2 and

e. 1,2 and 3

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Which of the following species will have a Lewis structure most like that of the hydronium ion , H3O?

a. NO3 -

b. NH3

c. SO3

d. CO3 2-

e. H2CO

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If one atom is replaced with a lone pair of electrons from which of the fundamental basic geometries below could you create a molecule having a triangular pyramidal shape?

a. linear

b. trigonal planar

c. octahedral

d. tetrahedral

e. trigonal bipyramidal

Watch Solution

Which of the following best represents the Lewis structure for ozone O 3?

a. 1

b. 2

c. 5

d. 4

e. 3

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In the Lewis structures of N2H2

a. There is a nitrogen-nitrogen triple bond

b. There is a nitrogen- nitrogen single bond

c. Each nitrogen has two nonbonding electron pairs (lone-pairs)

d. Each nitrogen has one nonbonding electron pair (lone-pair)

e. Each hydrogen has one nonbonding electron pair (lone pair) 

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Select the molecule which has one lone pair on the central atom

a. NH2 -

b. H2O

c. CH4

d. H3O+

e. BeCl2

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What is the total number of valence electrons in the Lewis structure of CH  2ClCH2Cl?

a. 14

b. 12

c. 18

d. 10

e. 26

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Please read each question carefully.

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The Lewis electron dot structure of SO4 2- shows how many lone pairs are present in the structure. Which of the following answers is correct?

a) 0

b) 1

c) 4

d) 12

e) none of the given answers

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Choose the best Lewis structure for ICl5 .

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Consider the Lewis Structure for aspartic acid (an amino acid found in proteins) for the next four questions (lone pairs are not shown).

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What is the molecular geometry of SeF5 - ?

1. see-saw

2. square pyramidal

3. octahedral

4. trigonal bipyramidal

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Which of the following has NO unshared pairs of electrons on the central atom?

1. BrO-

2. IF+

3. FNO2 (N is central)

4. SF-

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Which of the following has a trigonal planar geometry?

1. FNO2 (N is central)

2. SO3 2–

3. BrO3 – 

4. CH3

Watch Solution

The Lewis structure for N2H2 (HHNH) shows

1. two single bonds, one double bond and two unshared pairs

2. three single bonds and four unshared pairs

3. three single bonds and two unshared pairs

4. two single bonds, one double bond and dour unshared pairs

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