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Michigan State University CEM 141 MSU
CEM 141 Exam Questions and Answers 2026
Latest Update
3 Do isolated atoms/molecules exist in a state (solid, liquid, gas)? Ans: No
Do isolated atoms or molecules have melting/boiling points? Ans: No
States of matter, boiling/melting points are ? Ans: emergent properties
Emergent properties ... Ans: belong to a collection, but not individual
components.
If a solid reacts with gas, what state of matter will the product be? Ans: We
cannot tell
Similarities between LDFs & covalent bonds? Ans: caused by electrostatic
attraction of the electrons of one atoms to the nucleus of another
Differences between LDFs & covalent bonds? Ans: magnitude of the
attraction & how the electrons are arranged.
why do bonds form between atoms? Ans: because valence electrons are
attracted to the nuclei of other atoms
Covalent bonds Ans: Each nucleus is attracting both electrons (tug of war)
Bond length is most stable distance between the atoms (lowest potential
energy)
When bonds are formed... Ans: energy is released to the surroundings
What are the bonding models? Ans: Molecular orbital theory
Valence bond theory
Molecular Orbital Theory Ans: n atomic orbitals combine to give n molecular
orbitals
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atomic orbitals form constructively Ans: bonding molecular orbitals form,
lower energy than the atomic orbitals, more stable
atomic orbitals form destructively Ans: anti-bonding molecular orbitals
form, higher energy than the atomic orbitals, less stable
Both anti-bonding & bonding molecular orbitals... Ans: are in the same place
in space - just at different energies
A bond will form if... Ans: There are two electrons in a bonding molecular
orbital.
A bond will not form if.. Ans: There are two electrons in both anti-bonding
and bonding molecular orbital, cancelling out each other.
How to find bonds in MO Ans: # of bonds = (#e- in bonding MO - #e- in anti-
bonding MO) / 2
Properties of metals Ans: Shiny, conduct electricity/heat, malleable &
ductile, most grey, some colored (gold, copper), colorless (silver)
As the # of MOs increases... Ans: the energy gap between them decreases
In metals MOs Ans: form bands of almost continuous energy, allowing
electrons to move freely between MOs and over the whole system
metals are shiny because Ans: Electrons absorb and reemit photons of many
wavelengths.
Metals are malleable & ductile because Ans: atoms can move with respect to
one another, valence electrons act as glue
metals can conduct electricity because Ans: they have free electrons that
can move and carry the charge
In metals Ans: the bonding MOs (valence) overlaps with the anti-bonding
MOs (conduction)
In semi-conductors (metalloids) Ans: There is a small gap between the
bands
In insulators (diamond) Ans: there is a large energy gap between the bands.
© 2026 All rights reserved
Michigan State University CEM 141 MSU
CEM 141 Exam Questions and Answers 2026
Latest Update
3 Do isolated atoms/molecules exist in a state (solid, liquid, gas)? Ans: No
Do isolated atoms or molecules have melting/boiling points? Ans: No
States of matter, boiling/melting points are ? Ans: emergent properties
Emergent properties ... Ans: belong to a collection, but not individual
components.
If a solid reacts with gas, what state of matter will the product be? Ans: We
cannot tell
Similarities between LDFs & covalent bonds? Ans: caused by electrostatic
attraction of the electrons of one atoms to the nucleus of another
Differences between LDFs & covalent bonds? Ans: magnitude of the
attraction & how the electrons are arranged.
why do bonds form between atoms? Ans: because valence electrons are
attracted to the nuclei of other atoms
Covalent bonds Ans: Each nucleus is attracting both electrons (tug of war)
Bond length is most stable distance between the atoms (lowest potential
energy)
When bonds are formed... Ans: energy is released to the surroundings
What are the bonding models? Ans: Molecular orbital theory
Valence bond theory
Molecular Orbital Theory Ans: n atomic orbitals combine to give n molecular
orbitals
© 2026 All rights reserved
, 2 | Page
atomic orbitals form constructively Ans: bonding molecular orbitals form,
lower energy than the atomic orbitals, more stable
atomic orbitals form destructively Ans: anti-bonding molecular orbitals
form, higher energy than the atomic orbitals, less stable
Both anti-bonding & bonding molecular orbitals... Ans: are in the same place
in space - just at different energies
A bond will form if... Ans: There are two electrons in a bonding molecular
orbital.
A bond will not form if.. Ans: There are two electrons in both anti-bonding
and bonding molecular orbital, cancelling out each other.
How to find bonds in MO Ans: # of bonds = (#e- in bonding MO - #e- in anti-
bonding MO) / 2
Properties of metals Ans: Shiny, conduct electricity/heat, malleable &
ductile, most grey, some colored (gold, copper), colorless (silver)
As the # of MOs increases... Ans: the energy gap between them decreases
In metals MOs Ans: form bands of almost continuous energy, allowing
electrons to move freely between MOs and over the whole system
metals are shiny because Ans: Electrons absorb and reemit photons of many
wavelengths.
Metals are malleable & ductile because Ans: atoms can move with respect to
one another, valence electrons act as glue
metals can conduct electricity because Ans: they have free electrons that
can move and carry the charge
In metals Ans: the bonding MOs (valence) overlaps with the anti-bonding
MOs (conduction)
In semi-conductors (metalloids) Ans: There is a small gap between the
bands
In insulators (diamond) Ans: there is a large energy gap between the bands.
© 2026 All rights reserved
