Question 1

What is the point group of a AB2 molecule?

Accepted Answer

A)  If the molecule is linear, the point group is D∞h, but if it is bent then the point group is C2v. 
B)  If the molecule is linear, the point group is C∞h, but if it is bent then the point group is D2h. 
C)  If the molecule is linear, the point group is C∞h, but if it is bent then the point group is D∞h. 
A)  If the molecule is linear, the point group is D∞h, but if it is bent then the point group is C2v. 
B)  If the molecule is linear, the point group is C∞h, but if it is bent then the point group is D2h. 
C)  If the molecule is linear, the point group is C∞h, but if it is bent then the point group is D∞h. A

Question 2

A molecule with general formula AB2 has:

Accepted Answer

A)  3N-5 vibrational modes if it is linear and 3N-6 vibrational modes if it is non-linear. 
B)  5N-3 vibrational modes if it is linear and 6N-3 vibrational modes if it is non-linear 
C)  3N-3 vibrational modes if it is linear and 3N-5 vibrational modes if it is non-linear 
A)  3N-5 vibrational modes if it is linear and 3N-6 vibrational modes if it is non-linear. 
B)  5N-3 vibrational modes if it is linear and 6N-3 vibrational modes if it is non-linear 
C)  3N-3 vibrational modes if it is linear and 3N-5 vibrational modes if it is non-linear A

Question 3

Is tetrahedral SiF2Cl2 molecule polar and why?

Accepted Answer

A)  Yes, because it has a centre of inversion. 
B)  No, because it does not have a centre of inversion. 
C)  Yes, because it does not have a centre of inversion. 
A)  Yes, because it has a centre of inversion. 
B)  No, because it does not have a centre of inversion. 
C)  Yes, because it does not have a centre of inversion. C

Question 4

When is a vibrational mode of a molecule Raman active?

Accepted Answer

A)  When the vibrational mode has the same symmetry as a component of the molecule's electric dipole moment vector. 
B)  When the vibrational mode has the same symmetry as a component of the molecule's polarizability. 
C)  Vibrational modes of molecules are Raman active only; they cannot be IR active at the same time 
A)  When the vibrational mode has the same symmetry as a component of the molecule's electric dipole moment vector. 
B)  When the vibrational mode has the same symmetry as a component of the molecule's polarizability. 
C)  Vibrational modes of molecules are Raman active only; they cannot be IR active at the same time

Question 5

The molecule SiFClBrI is chiral because:

Accepted Answer

A)  it is has both tetrahedral geometry and tetrahedral symmetry but four different substituents on Si. 
B)  it has tetrahedral geometry, but not tetrahedral symmetry and hence has no Sn axis. 
C)  It has tetrahedral symmetry but not tetrahedral geometry and hence lacks the centre of inversion. 
A)  it is has both tetrahedral geometry and tetrahedral symmetry but four different substituents on Si. 
B)  it has tetrahedral geometry, but not tetrahedral symmetry and hence has no Sn axis. 
C)  It has tetrahedral symmetry but not tetrahedral geometry and hence lacks the centre of inversion.

Question 6

How can we differentiate bent and linear structures for AB2 molecules using IR spectroscopy?

Accepted Answer

A)  Bent structure will show both symmetric and antisymmetric vibrations, linear only antisymmetric. 
B)  Linear structure will show both symmetric and antisymmetric vibrations, bent only symmetric. 
C)  We cannot do conclusive differentiation without Raman spectroscopy. 
A)  Bent structure will show both symmetric and antisymmetric vibrations, linear only antisymmetric. 
B)  Linear structure will show both symmetric and antisymmetric vibrations, bent only symmetric. 
C)  We cannot do conclusive differentiation without Raman spectroscopy.

Question 7

Select the correct statement about symmetry elements:

Accepted Answer

A)  Centre of inversion is a point that is found in between the object and its inverse image; its symbol is Ci. 
B)  Rotation about a two-fold symmetry axis by 180F1F1F1S1F1F1F10 leaves the molecule unchanged. The symbol for this axis is C2. 
C)  One mirror plane, F1F1F1S1F1F1F10, cuts the molecule in two or more identical parts. Only planar molecules have mirror planes. 
A)  Centre of inversion is a point that is found in between the object and its inverse image; its symbol is Ci. 
B)  Rotation about a two-fold symmetry axis by 180F1F1F1S1F1F1F10 leaves the molecule unchanged. The symbol for this axis is C2. 
C)  One mirror plane, F1F1F1S1F1F1F10, cuts the molecule in two or more identical parts. Only planar molecules have mirror planes.

Question 8

To which point group does the tetrahedral SiF2Cl2 molecule belong?

Accepted Answer

A)  D4h 
B)  C2v 
C)  Td 
A)  D4h 
B)  C2v 
C)  Td

Question 9

Select the correct statement:

Accepted Answer

A)  Symmetry operations are actions that leave the molecule apparently unchanged. 
B)  Reflection operation has inversion centre as its symmetry element. 
C)  Identity operation involves rotating an object for 360F1F1F1S1F1F1F10 around a vertical axis. 
A)  Symmetry operations are actions that leave the molecule apparently unchanged. 
B)  Reflection operation has inversion centre as its symmetry element. 
C)  Identity operation involves rotating an object for 360F1F1F1S1F1F1F10 around a vertical axis.

Question 10

Looking at the character table for C3v point group, we see that z2 quadratic function has A1 symmetry. What does this tell us?

Accepted Answer

A)  The z-axis has the highest group order. 
B)  The rotation around z axis is a symmetrical operation. 
C)  The dz2 atomic orbital remains unchanged under all symmetry operations of this group. 
A)  The z-axis has the highest group order. 
B)  The rotation around z axis is a symmetrical operation. 
C)  The dz2 atomic orbital remains unchanged under all symmetry operations of this group.

What is the point group of a AB₂ molecule?

A molecule with general formula AB₂ has:

Is tetrahedral SiF₂Cl₂ molecule polar and why?

When is a vibrational mode of a molecule Raman active?

The molecule SiFClBrI is chiral because:

How can we differentiate bent and linear structures for AB₂ molecules using IR spectroscopy?

Select the correct statement about symmetry elements:

To which point group does the tetrahedral SiF₂Cl₂ molecule belong?

Select the correct statement:

Looking at the character table for C_3v point group, we see that z² quadratic function has A₁ symmetry. What does this tell us?

Atomic Structure

Molecular Structure and Bonding

The Structures of Simple Solids

Acids and Bases

Oxidation and Reduction

An Introduction to Coordination Compounds

Physical Techniques in Inorganic Chemistry

Periodic Trends

Hydrogen

The Group 1 Elements

The Group 2 Elements

The Group 13 Elements

The Group 14 Elements

The Group 15 Elements

The Group 16 Elements

The Group 17 Elements

The Group 18 Elements

The D-Block Elements

The D-Metal Complexes: Electronic Structure and Spectra

Coordination Chemistry: Reactions of Complexes

D-Metal Organometallic Chemistry

The F-Block Metals

Materials Chemistry and Nanomaterials

Green Chemistry

Biological Inorganic Chemistry

Inorganic Chemistry in Medicine

Filters

Exam 3: Molecular Symmetry

What is the point group of a AB2 molecule?

A molecule with general formula AB2 has:

Is tetrahedral SiF2Cl2 molecule polar and why?

When is a vibrational mode of a molecule Raman active?

The molecule SiFClBrI is chiral because:

How can we differentiate bent and linear structures for AB2 molecules using IR spectroscopy?

Select the correct statement about symmetry elements:

To which point group does the tetrahedral SiF2Cl2 molecule belong?

Select the correct statement:

Looking at the character table for C3v point group, we see that z2 quadratic function has A1 symmetry. What does this tell us?

Atomic Structure

Molecular Structure and Bonding

The Structures of Simple Solids

Acids and Bases

Oxidation and Reduction

An Introduction to Coordination Compounds

Physical Techniques in Inorganic Chemistry

Periodic Trends

Hydrogen

The Group 1 Elements

The Group 2 Elements

The Group 13 Elements

The Group 14 Elements

The Group 15 Elements

The Group 16 Elements

The Group 17 Elements

The Group 18 Elements

The D-Block Elements

The D-Metal Complexes: Electronic Structure and Spectra

Coordination Chemistry: Reactions of Complexes

D-Metal Organometallic Chemistry

The F-Block Metals

Materials Chemistry and Nanomaterials

Green Chemistry

Biological Inorganic Chemistry

Inorganic Chemistry in Medicine

Filters

What is the point group of a AB₂ molecule?

A molecule with general formula AB₂ has:

Is tetrahedral SiF₂Cl₂ molecule polar and why?

How can we differentiate bent and linear structures for AB₂ molecules using IR spectroscopy?

To which point group does the tetrahedral SiF₂Cl₂ molecule belong?

Looking at the character table for C_3v point group, we see that z² quadratic function has A₁ symmetry. What does this tell us?