High School
SAT
ACT
University
MCAT
LSAT
DAT
Wize University Chemistry Textbook > VSEPR Shapes and Polarity

VSEPR (Molecular Shapes)

Filling in a Skeletal StructurePrevious Section
Molecular PolarityNext Section
Popular Courses
Find My Course
0:00 / 0:00

VSEPR Theory


VSEPR aka Valence Shell Electron Pair Repulsion theory: states that repulsion of electron pairs (both bonds and lone pairs) in the valence shell will dictate the molecular geometry of a compound.


Wize Concept
To predict a molecular shape using VSEPR we need the BEST Lewis Structure!

Drawing the best Lewis Structure will provide us with two key pieces of information:
  • The number of lone pairs on the central atom
  • The number of bound atoms to the central atom
Once we have this information we can determine the electron geometry and the molecular shape as well as the bond angles of the molecule in question! These are all very common exam questions :)


PAGE BREAK

Electron Geometry (aka Orbital Geometry or Parent Shape)

Electron geometry is based on the number of electron groups around the central atom

EGs=number of lone pairs of electrons + number of bound atoms\boxed{EGs=\text{number of lone pairs of electrons + number of bound atoms}}
EGs are electron groups

Example:
How many electron groups does the C atom on the left have?


EGs=# of lone pairs of electrons + number of bound atoms
EGs=0 +2
EGs= 2

Watch Out!
The triple bond has no effect on EGs because we are counting the number of bound atoms, so whether there is a C bound to another C with a single bond, double bond, or triple bond, those will all just count as 1 EG!


PAGE BREAK

Molecular Shape

The shape of a molecule is determined by where the atoms are located.

Write the number of electron groups on the left side of the table.



Wize Tip
The tables in this lesson are very commonly tested on!
Take a few minutes to memorize these tables as you will likely see many questions relating to VSEPR theory on your exams!

PAGE BREAK
Write the number of electron groups on the left side of the table.


Note:

  • Wedges mean the bond is coming out of the page and dashes mean the bond is going back into the page.
  • LP=lone pairs of electrons
  • BA=bound atoms
  • Lone pairs give more push (are even more repelled by other electrons), which is why wee see the bond angles change slightly.

0:00 / 0:00

Example: Parent and Molecular Shape

Determine the parent shape and molecular shape for the following.

a) NH3



Electron geometry: tetrahedral
Molecular shape: trigonal pyramidal

b) SCl2




Electron geomtery: tetrahedral
Molecular shape: bent

PAGE BREAK

c) IF7


Electron geometry: pentagonal bipyramidal
Molecular shape: pentagonal bipyramidal



d) SF4


Electron geometry: trigonal bipyramidal
Molecular shape: see-saw


0:00 / 0:00

Example: VSEPR and Molly

MDMA (3,4-methylenedioxy-methamphetamine) or “Molly” is a psychoactive drug commonly used for recreational purposes, which has been investigated as a treatment for PTSD. It functions by triggering serotonin release and inhibiting serotonin reuptake in the human brain, causing euphoric and empathogenic effects on the user. The structure of MDMA is shown below.




a) What is the molecular shape of the nitrogen atom in MDMA?


Trigonal Pyramidal

b) Approximate the O-C-O bond angle in MDMA?


109.5∘109.5^\circ

c) How many atoms with a trigonal planar electron geometry are there in MDMA?


6


Practice: VSEPR Shapes

Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to answer the next three questions

1. PH3

2. AlH4-

3. IO3-




Which of the following has a central atom with a tetrahedral electron-pair geometry?

Practice: Bond Angle Identification

Which of the following compounds has a 120o bond angle?

VSEPR and Molecular Shapes - Cheatsheet

The last shape when 7 atoms are bound to the central atom: pentagonal bipyramidal
Extra Practice
MDMA (3,4-methylenedioxy-methamphetamine) or “Molly” is a psychoactive drug commonly used for recreational purposes, which has been investigated as a treatment for PTSD. It functions by triggering serotonin release and inhibiting serotonin reuptake in the human brain, causing euphoric and empathogenic effects on the user. The structure of MDMA is shown below.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Simple VSEPR Shapes
Draw the Lewis Structure, Perspective Diagram, and identify the molecular shape of the following molecules.
a) SiH4
b) AsBr5
Lone Pairs in VSEPR Theory
Determine the VSEPR shape of the: Ni, O and C atoms for complete Lewis structure of the molecule below.
Lone Pairs in VSEPR Theory
Determine the VSEPR and molecular shapes of the: Ni, O and C atoms for complete Lewis structure of the molecule below.
VSEPR
Using VSEPR theory predict the molecular shape of the cation in tetramethylammonium iodide, [(CH3)4N]+ I-
.
VSEPR
The Lewis structure of a simple organic fragment is shown below:
What is the NCO bond angle?
VSEPR
The Lewis structure of a simple organic fragment is shown below:
What is the HCH angle of the CH3 group?
Hybridization, bond angle
1. What are the hybridization of each of the N atom in N3― and what is the NNN bond angle?
2. What are the hybridization of each of the atoms in HOCN? What are the HOC and OCN bond angles?
Choose the correct option:
Hybridization, VSEPR
For the natural product Ottelione A, denote the hybridization, approximate bond angle and VSEPR notation for the highlighted atoms.
Which of the following compounds would have a seesaw molecular geometry (shape).
A. IBr4–
B. TeH4
MDMA (3,4-methylenedioxy-methamphetamine) or “Molly” is a psychoactive drug commonly used for recreational purposes, which has been investigated as a treatment for PTSD. It functions by triggering serotonin release and inhibiting serotonin reuptake in the
human brain, causing euphoric and empathogenic effects on the user. The structure of MDMA is shown below.
Which of the following statements are true?
VSEPR
Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to answer the next three questions
1. PH3
2. AlH4-
Lewis Structure: Geometry Practice
Three compounds are given below. Write the dot structure and draw the molecular geometry for each of these molecules. Also include a descriptive name to describe the molecular shape: bent, T-shaped, see-saw, trigonal planar, trigonal pyramid, trigonal bipyramid, square planar, square pyramid, tetrahedral, or octahedral.
Consider the following reaction of silicon tetrafluoride:
SiF4+F−→SiF5−\rm SiF_4 + F^- \to {SiF_5}^-
Give the AXnEm notation and name of the molecular geometry around Si\rm Si before and after this reaction. Are either of these species polar?
Hybridization, VSEPR
Consider XeO3 and answer the following:
a. What is the approximate O-Xe-O bond angle?
b. What is the hybridization of Xe?
Practice: VSEPR
Draw the shapes of the following molecules/ions using VSEPR theory and comment on their polarities:
1. SO2
2. H2O
VSEPR: Molecular Polarity
Answer the following questions for the molecule: XeO2F2.
VSEPR: Bond Angles
The structures of TeF5- and SF6 have identical VSEPR shapes, yet TeF5- has bond angles of 79o and SF6 has bond angles of 90o. Explain the difference.
VSEPR
Determine the VSEPR shape and molecular shape of XeCl2F2.
VSEPR
Determine the VSEPR shape for the following molecules.
a) AlH3
b) SeCl6
Lone Pairs in VSEPR Theory
Determine the VSEPR and molecular shapes of the: Ni, O and C atoms for complete Lewis structure of the molecule below.
Lone Pairs in VSEPR Theory
For each of the following molecules, determine the VSEPR shape and the molecular shape.
a) COS (C is the central atom)
b) POCl3
Lone Pairs in VSEPR Theory
Match each of the following molecules to the correct molecular shape (remember, N (# e- pairs) = #lone pairs + #bonds). BUT, for molecular shape, lone pairs are NOT included.
Lone Pairs in VSEPR Theory
Match each of the following molecules to the correct VSEPR shape (remember, N (# e- pairs) = #lone pairs + #bonds).
Simple VSEPR Shapes
Determine the VSEPR shape of the following molecules.
a) SiH4
b) AsBr5
Organic Compounds
Answer the following questions on the organic structure below.
Lone Pairs in VSEPR Theory
For each of the following molecules, determine the VSEPR shape and the molecular shape.
a) BrCl5
b) H2S
VSEPR
Using VSEPR theory predict the molecular shape of the cation in tetramethylammonium iodide, [(CH3)4N]+ I-
.
VSEPR
Question refers to the figure below. All of these structures have five (5) electron domains.
Which element M will lead to an MF3 molecule with shape D above?
VSEPR: Molecular Geometry
Name the molecular geometry of the following compounds
a) NO3−\rm {NO_3}^-
b) CH4\rm CH_4
VSEPR
Next question concerns the molecule acrylonitrile, C3H3N, shown below.
The H-C-H an C-C-C bond angles in a molecule of acrylonitrile are closest to what pair of values
respectively?
Lewis Structures: VSEPR
Predict the shape of BeCl2
VSEPR
MDMA (3,4-methylenedioxy-methamphetamine) or “Molly” is a psychoactive drug commonly used for recreational purposes, which has been investigated as a treatment for PTSD. It functions by triggering serotonin release and inhibiting serotonin reuptake in the
human brain, causing euphoric and empathogenic effects on the user. The structure of MDMA is shown below.
How many atoms have trigonal planar electron geometry in MDMA?
VSEPR: Molecular Polarity
Is SO2 polar or non-polar?
What is the molecular shape?
What is the electron geometry?
Lewis Structures: VSEPR
Which of the following compounds of xenon has exactly one nonbonding pair of electrons on the xenon
atom?
VSEPR
Next question refers to the figures below. All of these structures have five (5) electron domains.
Which of these molecular shapes best represents the shape of the molecule SeF4?
VSEPR
Which of these AB4 molecular geometries is observed for XeF4?
VSEPR
The Lewis structure of a simple organic fragment is shown below:
What is the HCH angle of the CH3 group?
VSEPR
The Lewis structure of a simple organic fragment is shown below:
What is the NCO bond angle?
VSEPR
MDMA (3,4-methylenedioxy-methamphetamine) or “Molly” is a psychoactive drug commonly used for recreational purposes, which has been investigated as a treatment for PTSD. It functions by triggering serotonin release and inhibiting serotonin reuptake in the
human brain, causing euphoric and empathogenic effects on the user. The structure of MDMA is shown below.
What is the molecular shape of the nitrogen atom in MDMA?
Which of the following compounds would have a seesaw molecular geometry (shape).
A. IBr4–
B. TeH4
VSEPR: Molecular Polarity
What is the VSEPR shape for ClF3? Is this a polar molecule?
VSEPR
Determine the VSEPR shape for NH3.
VSEPR
Determine the VSEPR structure for SF4.
VSEPR
What VSEPR shape does XeF2 take?
VSEPR
What VSEPR shape does ICl3 take?
VSEPR
What is the VSEPR structure for NH3.
VSEPR: Expanded valence
Give the VSEPR geometry of PF5.
VSEPR
Which of the following molecules has a trigonal bipyramidal electron geometry?
VSEPR: Bond Angle
Estimate which bond angle is smallest based on the VSEPR model.
VSEPR: Molecular Polarity
For the molecule, [Tel4]2-, answer the following questions
VSEPR
Draw the VSEPR diagram for each molecule. Identify the hybridization of the central atom.
PCl5                 CO2                  BF3                 SF4PCl_5\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ CO_2\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ BF_3\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ SF_4
VSEPR
1) Provide a prospective drawing for the following compounds and give the parent shape and molecular shape
a) IF7
b) SF4
VSEPR
A molecule with the general shape of AX3E2\rm AX_3E_2 has what molecular geometry?
VSEPR
The electronic geometry of PO43−\rm {PO_4}^{3-} according to VSEPR theory is:
VSEPR: Polarity
Is H2O a polar molecule? Use a VSEPR structure to determine your answer and choose the option with the correct molecular shape.
VSEPR
What is the molecular geometry of NH3 ?
VSEPR: Molecular polarity
Name the molecular geometry of the following compounds and determine whether each is polar.
a) NO3−NO_3^-
b) CH4CH_4
VSEPR
Which of the following molecules has a trigonal bipyramidal electron geometry?
VSEPR: Polarity
For the compounds below list the molecular shape and whether it is polar or non-polar.
VSEPR: Bond Angle Identification
Which of the following compounds has a 120o bond angle?
VSEPR: Practice
A compound has two lone pairs and is bound to four other atoms. What is the molecular shape of this compound?
VSEPR and Lewis Structure
SF2Cl4 exists as two isomers. One is polar, one is non-polar. Draw a 3-D representation of both isomers below.
VSEPR
Which element M, in the compound MF5 will lead to a trigonal bipyramidal molecular shape?
VSEPR
What is the approximate F-S-F angle in SF6?
VSEPR
Which of the following molecules has a square based pyramidal molecular shape?
VSEPR
The angles labelled a, b and c are approximately _ _ and _ respectively.
Which of the following compounds would have a seesaw molecular geometry (shape).
Lewis Structure: Practice
1) Draw Lewis structures for the following molecules
2) List the molecular shape and electron geometry for each
a) NH3.
Draw Lewis structures and give the other information requested for the following:
NO3-. Polar or nonpolar molecule?
BrF5. Polar or nonpolar molecule? Geometry?
VSEPR: Molecular polarity
Consider the following reaction of silicon tetrafluoride:
SiF4+F−→SiF5−\rm SiF_4 + F^- \to {SiF_5}^-
Give the AXnEm notation and name of the molecular geometry around Si\rm Si before and after this reaction. Are either of these species polar?
General Bonding Concepts
Provide a prospective drawing for the following compounds and give the parent shape (or electron geometry) and molecular shape
a) IF7
b) SF4
How many carbon atoms with a bent shape are there in the
molecule of 3-methyl-3-penten-1-ol given its line drawing ?
VSEPR
What is the molecular geometry of SF4\text{SF}_4 ?
Lewis Structures: VSEPR
If a molecule has the formula XBr4−\text{XBr}_ 4^- with a see-saw molecular geometry, what is the best choice for the identity of XX?
Name the molecular geometry of the following compounds
a) NO3−\rm {NO_3}^-
b) CH4\rm CH_4
MDMA (3,4-methylenedioxy-methamphetamine) or “Molly” is a psychoactive drug commonly used for recreational purposes, which has been investigated as a treatment for PTSD. It functions by triggering serotonin release and inhibiting serotonin reuptake in the
human brain, causing euphoric and empathogenic effects on the user. The structure of MDMA is shown below.
VSEPR
Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to
answer the following question: O3, NCl3, N3–
Which of the following will have bond angles of 180 °?
VSEPR
Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to
answer the following question: O3, NCl3, N3–
Which of the following has a tetrahedral molecular shape?
VSEPR
Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to
answer the following questions: O3, NCl3, N3-
Which of the following has trigonal planar VSEPR geometry?
VSEPR
Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to answer the following question
Which of the following molecules is/are polar?
i) CF4
VSEPR
Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to answer the following questions: CF4, SeF4, KrF4
Which of the following has a square planar molecular shape?
VSEPR
Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to answer the following questions: CF4, SeF4, KrF4
Which of the following has a tetrahedral electron-pair (VSEPR) geometry?
VSEPR
Use the molecular structure of CH3NCH2 to asnwer the following question
This structure does not show lone pairs, however all bonds and non-zero formal charges are shown.
Which of the choices below correctly identifies the electron-pair geometries of the atoms indicated?
VSEPR
Consider the VSEPR for the “best” Lewis diagrams for the following species and use them to answer the next three questions
a) PH3
b) AℓH4-
VSEPR: σ and π Frameworks with Triple Bonds
Solve the following two part question, regarding the line drawing shown below.
Part 1:
Part 2:
Molecular Polarity: Permanent dipole
The Lewis structure of formyl bromide is given below. Which of the vectors corresponds to direction of its NET molecular dipole?
Molecular Polarity and VSEPR
Molecular Polarity and VSEPR
Consider the best Lewis diagrams for the following chemical species to answer the next two questions
1. ClF3
Consider the polyatomic ion SO32- and answer questions.
The O-S-O bond angles in this ion are (approximately)?
Consider the polyatomic ion SO32- and answer questions.
The molecular geometry is ______.
VSEPR: Hybridization & Geometry
Fill in the table for the following compounds:
SF6
NH3
What is the molecular shape predicted by VSEPR for ICl3?
Molecular Geometry V
What is the molecular shape of CO32- ?
Which is the correct geometry of the following compounds: PBr3, BH4-, NMe4+