Michigan State University
CEM 141 CEM 141 Exam 3 Questions and
Answers 2026 Latest Update
Do isolated atoms or molecules exist in a state (solid, liquid or gas)?— Ans:
No, 1 isolated atom does not exist in a state because they are not interacting
with anything
Do isolated atoms or molecules have melting or boiling points?— Ans: No
When do atoms have emergent properties?— Ans: When they interact to
form larger collections
T/F: Emergent properties belong to a collection, but not the individual
components— Ans: True
How many atoms must interact to provide emergent properties?— Ans:
There is no specific number, just need multiple atoms
If a solid reacts with a gas, what state of matter will the product be?— Ans:
We cannot tell from the information given, properties of the product are
unrelated to the properties of the reactant
What do the properties of any substance depend on?— Ans: They depend on
the bonding/interaction that exist within that substance
How do we predict the properties of any substance?— Ans: We need to
know the bonding interactions of the reactants
T/F: The interaction between two hydrogen atoms is much stronger than
two helium atoms— Ans: True
What are the differences between covalent bonds and london dispersion
forces?— Ans: The magnitude of the attraction and how the electrons are
arranged in the new species (which is formed by the interaction)
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Why do bonds form between atoms?— Ans: because valence electrons are
attracted to the nuclei of other atoms
What happens when two hydrogen atoms interact?— Ans: They form a
covalent bond
Is each nucleus of hydrogen atoms sharing electrons, or is it more like a tug
of war?— Ans: Tug of war
What is bond length?— Ans: The most stable distance between the atoms -
ie: lowest potential energy
What does the molecular orbital (MO) theory focus on?— Ans: The wave
nature of electrons
In MO theory, n atomic orbitals combine to give...— Ans: n molecular
orbitals (the same number of orbitals)
What happens when atomic orbitals combine constructively?— Ans: Bonding
molecular orbitals form
Bonding MOs are ___________ energy than the atomic orbitals— Ans: lower
Electrons in bonding orbitals make the species more...— Ans: stable
What happens when atomic orbitals combine destructively?— Ans: They
form antibonding molecular orbitals
Antibonding orbitals are _________ in energy than the atomic orbitals— Ans:
higher
Electrons in antibonding orbitals make the species less...— Ans: stable
T/F: MO theory accounts for the wave nature of electrons, and it states that
atomic orbitals combine just like waves in phase and out of phase to form
molecular orbitals.— Ans: True
T/F: Both bonding and antibonding orbitals are in the same place in space -
just at different energies— Ans: True
Why do two H atoms form a bond?— Ans: look at diagram
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