12. Molecular Shapes & Valence Bond Theory

Molecular Geometry

VSEPR and Molecular Geometry

Determine the molecular geometry for the following molecule:CHClO.

Six Electron Groups:Octahedral, Square pyramidal, Square planar

For each molecule (a)–(f), indicate how many different
electron-domain geometries are consistent with the molecular
geometry shown.
a. <img src="https://lightcat-files.s3.amazonaws.com/problem_images/167e08f8f93351f1-1661343299517.jpg" alt="" />

Two Electron Groups:&nbsp;Linear

(a) Explain why BrF4- is square planar, whereas BF4- is tetrahedral.

Five Electron Groups:Trigonal Bipyramidal, See-saw, T-shaped, Linear

Give the electron-domain and molecular geometries for the
following molecules and ions: (a) BeF2

Draw an electron-dot structure for each of the following 
substances, and predict the molecular geometry of every 
nonterminal atom. 
(a) F3S¬S¬F

Molecular Geometry Concept 3

Molecular Geometry Concept 2

VSEPR Theory: Determining the 3D Shape of Molecules

Determine the geometry about each interior atom in each molecule 
and sketch the molecule. (Skeletal structure is indicated in 
parentheses.) 
c. NH2CO2H (H2NCOOH both O atoms attached to C)

Molecular Geometry Concept 4

Reaction of gaseous fluorine with compound X yields a sin- gle product Y, whose mass percent composition is 61.7% F and 38.3% Cl. (b) Draw an electron-dot structure for Y, and predict the geometry around the central atom.

Determine the molecular geometry for the following molecule:IF4–.

Determine the geometry about each interior atom in each molecule 
and sketch the molecule. (Skeletal structure is indicated in 
parentheses.) 
b. CH3CO2CH3 (H3CCOOCH3 One O atom attached to 2nd C 
atom; the other O atom is bonded to the 2nd and 3rd C atom)

Determine the molecular geometry and sketch each molecule 
or ion, using the bond conventions shown in “Representing 
Molecular Geometries on Paper” in Section 10.4. 
c. PF5

The figure that follows contains ball-and-stick drawings of
three possible shapes of an AF4 molecule. (a) For each shape,
give the electron-domain geometry on which the molecular
geometry is based. 
i. <img src="https://lightcat-files.s3.amazonaws.com/problem_images/75f34d156bad2b36-1664544481712.jpg" alt="" />

Determine the molecular geometry for the following molecule:SeH2Cl2

The dichromate ion, Cr2O72-, has neither Cr¬Cr nor 
O¬O bonds. 
(b) How many outer-shell electrons does each Cr atom have 
in your electron-dot structure? What is the likely geometry 
around the Cr atoms?

Determine the molecular geometry and sketch each molecule 
or ion using the bond conventions shown in “Representing Molecular 
Geometries on Paper” in Section 10.4. 
c. IF2-

Molecular Geometry Example 1

Consider the molecule PF4Cl. (c) Predict the molecular geometry 
of PF4Cl. How did your answer for part (b) influence 
your answer here in part (c)?

9.1 VSEPR Theory and Molecular Geometry | General Chemistry

A potential replacement for the chlorofluorocarbon refrigerants 
that harm the Earth’s protective ozone layer is a compound 
called E143a, or trifluoromethyl methyl ether, F3COCH3. 
Draw an electron-dot structure for F3COCH3, and predict the 
geometry around both the carbons and the oxygen.

Determine the molecular geometry about each interior atom 
and sketch each molecule. 
c. N2H4 (skeletal structure H2NNH2)

The figure that follows contains ball-and-stick drawings of
three possible shapes of an AF4 molecule. (a) For each shape,
give the electron-domain geometry on which the molecular
geometry is based. 
ii.

Understanding Molecular Geometry

Determine the molecular geometry for the following molecule:FSSF.

Molecular Geometry Example 3

Molecular geometry - Real Chemistry

Three of the following molecular models have a tetrahedral central
atom, and one does not. Which is the odd one? (There may
be a “hidden” atom directly behind a visible atom in some cases.)
(a) <img src="" alt="" />
(b) <img src="" alt="" />
(c) <img src="" alt="" />
(d) <img src="" alt="" />

Determine the geometry about each interior atom in each molecule 
and sketch the molecule. (Skeletal structure is indicated in 
parentheses.) 
b. CH3OCH3 (H3COCH3)

Determine the molecular geometry and sketch each molecule 
or ion, using the bond conventions shown in “Representing 
Molecular Geometries on Paper” in Section 10.4. 
d. IF4+

Determine the molecular geometry and sketch each molecule 
or ion, using the bond conventions shown in “Representing 
Molecular Geometries on Paper” in Section 10.4. 
b. SCl6

Molecular Geometry Concept 5

What geometric arrangement of charge clouds do you expect 
for atoms that have the following number of charge clouds? 
(a) 3 (b) 5 (c) 2 (d) 6

The following ball-and-stick molecular model is a representation
of acetaminophen, the active ingredient in such over-thecounter
headache remedies as Tylenol. 1Red = O, gray = C,
blue = N, ivory = H.2
(c) What is the geometry around each carbon?
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/fbef682fe8569314-1670861169608.jpg" alt="" />

The compound C3H4 has two double bonds. Describe its bonding
and geometry, using a valence bond approach.

Values of Ea = 6.3 kJ>mol and A = 6.0 * 108>1M # s2 
have been measured for the bimolecular reaction: 
NO1g2 + F21g2S NOF1g2 + F1g2 
(b) The product of the reaction is nitrosyl fluoride. Its formula 
is usually written as NOF, but its structure is actually 
ONF. Is the ONF molecule linear or bent?

Molecular Geometry Example 2

Molecular Shapes

(b) The PCl3 molecule is trigonal pyramidal, 
while ICl3 is T-shaped. Which of these molecules is flat?

Predict the molecular geometry of each of the following molecules: 
(b) H O C O C O O H <img src="https://lightcat-files.s3.amazonaws.com/problem_images/93d1d297e096bc26-1661344361878.jpg" alt="" />

Each ball-and-stick model shows the electron and molecular geometry of a generic molecule. Explain what is wrong with each 
molecular geometry and provide the correct molecular geometry, 
given the number of lone pairs and bonding groups on the 
central atom. 
(c) <img src="https://lightcat-files.s3.amazonaws.com/problem_images/de1d4f701e7e6587-1660145839097.jpg" alt="" />

An AB2 molecule is described as having a tetrahedral geometry.
(b) Based on the information given, which of the following
is the molecular geometry of the molecule: (i) linear, (ii) bent,
(iii) trigonal planar, or (iv) tetrahedral?

What shape do you expect for molecules that meet the following 
descriptions? 
(a) A central atom with two lone pairs and three bonds to 
other atoms 
(b) A central atom with two lone pairs and two bonds to 
other atoms 
(c) A central atom with two lone pairs and four bonds to 
other atoms

 Count the number of hybrid orbitals around the central atom with this type of hybridization. 

 Correct, each hybridized orbital can form sigma bonds or be occupied by a lone pair. 

 The number of orbitals used in the hybridization process is equal to the maximum number of sigma bonds that can form. 

What is the maximum number of sigma bonds that a central atom with sp3d hybridization can form?

Four Electron Groups:Tetrahedral, Trigonal pyramidal, Bent = V-shaped = Angular

What is the geometry around the central atom in each of the
following molecular models?
(a) <img src="https://lightcat-files.s3.amazonaws.com/problem_images/058b4b863f810605-1670858988441.jpg" alt="" />

The figure that follows contains ball-and-stick drawings of 
three possible shapes of an AF4 molecule. (c) Which of the 
following elements will lead to an AF4 molecule with the 
shape in (iii): Be, C, S, Se, Si, Xe? 
i. <img src="https://lightcat-files.s3.amazonaws.com/problem_images/28dd4eacf9625c07-1661344240500.jpg" alt="" /> 
ii. <img src="" alt="" /> 
iii. <img src="" alt="" />

Three Electron Groups:Trigonal Planar, Bent = V-shaped = Angular

Determine the geometry about each interior atom in each molecule 
and sketch the molecule. (Skeletal structure is indicated in 
parentheses.) 
c. H2O2 (HOOH)

Molecular Geometry Concept 1

Determine the molecular geometry and sketch each molecule 
or ion using the bond conventions shown in “Representing Molecular 
Geometries on Paper” in Section 10.4. 
d. IBr4-

The figure that follows contains ball-and-stick drawings of
three possible shapes of an AF4 molecule. (a) For each shape,
give the electron-domain geometry on which the molecular
geometry is based. 
iii. <img src="https://lightcat-files.s3.amazonaws.com/problem_images/23391b297db70105-1676662894611.jpg" alt="" />

 There are two lone pairs of electrons on the central Xe atom. 

 There are six electrons groups on the central Xe atom. 

 Correct, there are two lone pairs on the central Xe atom. 

 Draw the Lewis structure and apply VSEPR theory. 

What is the molecular shape of XeF4?

Give the electron-domain and molecular geometries for the 
following molecules and ions: (c) NO2-

Determine the molecular geometry about each interior atom 
and sketch each molecule. 
a. N2

An AB5 molecule adopts the geometry shown here. (b) Do you think there are any nonbonding electron pairs on atom A? 
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/d301702dfa6654fc-1664547639536.jpg" alt="" />

 Check the number of lone pairs on the central atom. 

 Correct, there are two bonding groups and two lone pairs on the central atom. 

 You may be thinking about the electron pair geometry. 

 T-shaped geometry requires three bonding groups on the central atom. 

 Draw the Lewis structure and use the number bonding groups and lone pairs to determine the molecular geometry according to VSEPR theory. 

What is the molecular geometry of SBr2?

For each molecular geometry, list the number of total electron
groups, the number of bonding groups, and the number of lone
pairs on the central atom.
(c) <img src="https://lightcat-files.s3.amazonaws.com/problem_images/3a199ddc94f402e5-1660058200646.jpg" alt="" />

Draw the Lewis structure for each of the following molecules
or ions, and predict their electron-domain and molecular
geometries: (e) XeF2

Determine the molecular geometry about each interior atom
and draw each molecule. (Skeletal structure is indicated in
parentheses.)
a. C2H2 (skeletal structure HCCH) 
b. C2H4 (skeletal structure H2CCH2) 
c. C2H6 (skeletal structure H3CCH3)

Determine the molecular geometry about each interior atom 
and sketch each molecule. 
b. N2H2 (skeletal structure HNNH)

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1. Intro to General Chemistry

2. Atoms & Elements

3. Chemical Reactions

4. BONUS: Lab Techniques and Procedures

5. BONUS: Mathematical Operations and Functions

6. Chemical Quantities & Aqueous Reactions

7. Gases

8. Thermochemistry

9. Quantum Mechanics

10. Periodic Properties of the Elements

11. Bonding & Molecular Structure

13. Liquids, Solids & Intermolecular Forces

14. Solutions

15. Chemical Kinetics

16. Chemical Equilibrium

17. Acid and Base Equilibrium

18. Aqueous Equilibrium

19. Chemical Thermodynamics

20. Electrochemistry

21. Nuclear Chemistry

22. Organic Chemistry

23. Chemistry of the Nonmetals

24. Transition Metals and Coordination Compounds

[BOOK CHEM] Clutch Version

MO Theory: Homonuclear Diatomic Molecules

Homonuclear Diatomic Molecules are composed of 2 identical elements bonded together.

Equatorial and Axial Positions

Covalent compounds with 5 or 6&nbsp;electron groups have equatorial and axial positions for surrounding elements

MO Theory: Heteronuclear Diatomic Molecules

Heteronuclear Diatomic Molecules are composed of 2 different elements bonded together.

Bond Angles

Bond Angles&nbsp;result from surrounding elements and lone pairs around the central element positioning themselves at an optimal distance.&nbsp;

Molecular Orbital Theory

Molecular Orbital Theory&nbsp;allows us to predict the distribution of electrons within a molecule.&nbsp;

MO Theory: Bond Order

Molecular Orbital Diagrams can be used to determine the bond order of a molecule.

Electron Geometry

The simplest system for geometrical shapes that focuses on the number of electron groups around the central atom.

Hybridization

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

True Shape of Molecules that takes into account differences&nbsp;in repulsion between lone pairs and surrounding elements.