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Michigan State University
CEM 141 CEM 141 EXAM 3 MSU Questions
and Answers 2026 Latest Update
T/F: Covalent bonds are present only when atomic orbitals interact
constructively. Ans: True.
Binding in Diamond Ans: Each carbon forms 4 bonds to 4 identical carbons;
tetrahedral; sp3
Valence Bond Theory Ans: The idea that covalent bonds are formed when
orbitals of different atoms overlap.
T/F: Electrons are localized in molecular orbital. Ans: False
T/F: Electrons are localized in Valence Bond. Ans: True
T/F: When the hybrid orbitals combine, there is a large gap between the
bonding and anti bonding orbitals. Ans: True
Bonding in Tetrahedral C results in..... Ans: Sigma bonds.
Bonding in Graphite Ans: 3 sp2 orbitals; trigonal planar; sigma bond
Is graphite localized ? Ans: Has a localized sigma bond network but has a
delocalized pi network over the whole sheet of atoms.
What does a larger electron cloud provide? Ans: Higher boiling point and
more surface area to overcome LDF's.
Can you rotate around a double bond? Ans: No - bonds will break.
What is a sigma bond? Ans: Single covalent bond (sp2-sp2 overlap).
What is a Pi Bond? Ans: Sideways overlap of p orbitals that occur in a double
or triple bond.
Formal Charge = Ans: Valence electrons - # of bonds - non bonded electrons
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Formal Charge on OH-? Ans: O: FC = 6 - 1 - 6 = -1.
Valence Shell Electron Pair Repulsion (VSEPR) Ans: Assume all centers of
electrons density repel each other and that there is a minimum energy
arrangement that the atom will naturally take up.
T/F: Multiple bonds count as one center of electron density in VSEPR. Ans:
True.
What hybridization is tetrahedral? Ans: SP3.
T/F: If there are no lone pairs on the central atom, the electron center
geometry and shape are the SAME. Ans: True.
Electronegativity Ans: Ability of an element to attract electrons to itself in a
bond.
Does electronegativity increase or decrease across a period? Ans: Increase.
Does electronegativity increase or decrease down a group? Ans: Decreases.
Polar Bonds Ans: When 2 atoms of different electronegativities bond, the
electrons are not shared equally (Dipole = polar)
Is a C-H bond polar? Ans: No.
Are bond Dipoles vector quantities? Ans: Yes, must have magnitude and
direction.
How to determine molecular polarity? Ans: 1. Draw Lewis Structure
2. Determine the electron pair geometry
3. Determine molecular shape
4. Determine the bond polarities
5. Add up the bond polarities
6. Figure out the molecular polarity.
What kind of intermolecular force is present in non-polar molecules? Ans:
ONLY LDF'S.
© 2026 All rights reserved
Michigan State University
CEM 141 CEM 141 EXAM 3 MSU Questions
and Answers 2026 Latest Update
T/F: Covalent bonds are present only when atomic orbitals interact
constructively. Ans: True.
Binding in Diamond Ans: Each carbon forms 4 bonds to 4 identical carbons;
tetrahedral; sp3
Valence Bond Theory Ans: The idea that covalent bonds are formed when
orbitals of different atoms overlap.
T/F: Electrons are localized in molecular orbital. Ans: False
T/F: Electrons are localized in Valence Bond. Ans: True
T/F: When the hybrid orbitals combine, there is a large gap between the
bonding and anti bonding orbitals. Ans: True
Bonding in Tetrahedral C results in..... Ans: Sigma bonds.
Bonding in Graphite Ans: 3 sp2 orbitals; trigonal planar; sigma bond
Is graphite localized ? Ans: Has a localized sigma bond network but has a
delocalized pi network over the whole sheet of atoms.
What does a larger electron cloud provide? Ans: Higher boiling point and
more surface area to overcome LDF's.
Can you rotate around a double bond? Ans: No - bonds will break.
What is a sigma bond? Ans: Single covalent bond (sp2-sp2 overlap).
What is a Pi Bond? Ans: Sideways overlap of p orbitals that occur in a double
or triple bond.
Formal Charge = Ans: Valence electrons - # of bonds - non bonded electrons
© 2026 All rights reserved
, 2 | Page
Formal Charge on OH-? Ans: O: FC = 6 - 1 - 6 = -1.
Valence Shell Electron Pair Repulsion (VSEPR) Ans: Assume all centers of
electrons density repel each other and that there is a minimum energy
arrangement that the atom will naturally take up.
T/F: Multiple bonds count as one center of electron density in VSEPR. Ans:
True.
What hybridization is tetrahedral? Ans: SP3.
T/F: If there are no lone pairs on the central atom, the electron center
geometry and shape are the SAME. Ans: True.
Electronegativity Ans: Ability of an element to attract electrons to itself in a
bond.
Does electronegativity increase or decrease across a period? Ans: Increase.
Does electronegativity increase or decrease down a group? Ans: Decreases.
Polar Bonds Ans: When 2 atoms of different electronegativities bond, the
electrons are not shared equally (Dipole = polar)
Is a C-H bond polar? Ans: No.
Are bond Dipoles vector quantities? Ans: Yes, must have magnitude and
direction.
How to determine molecular polarity? Ans: 1. Draw Lewis Structure
2. Determine the electron pair geometry
3. Determine molecular shape
4. Determine the bond polarities
5. Add up the bond polarities
6. Figure out the molecular polarity.
What kind of intermolecular force is present in non-polar molecules? Ans:
ONLY LDF'S.
© 2026 All rights reserved
