CEM 141 Chapter 3 Test Exam 2025/2026 ACTUAL COMPLETE
REAL EXAM ELABORATIONS QUESTIONS AND VERIFIED
ANSWERS (100% CORRECTLY SOLVED ) 2025 LATEST
UPDATE !!
How many bonds form between 2 O atoms? - ANSWER-
2 bonds (only
concerned with valence
electrons)
What properties do metals have? -
ANSWER-1. shiny
2. conduct electricity
and heat
a. because electrons can
move freely
3. malleable and
ductile
a. malleable because atoms can move with respect to
one another
,4. may be colored (gold, copper)- silver is colorless (like
most metals)
How does bonding in metals explain their properties? -
ANSWER-1. lots of atomic orbitals combine with each other to
form molecular orbitals (an equal number)
2. As the number of Molecular Orbital's increases, the energy
distance between them decreases and they form bands of
Molecular Orbitals (of almost continuous energy)
3. electrons can move freely between Molecular Orbitals and
over whole system
Why are metals shiny? (properties of metals) - ANSWER-1.
Absorption of a photon will promote an electron to a higher
energy level
2. It immediately falls back down-emitting a photon-the metal
shines
3. the metal interacts with light of many wavelengths, so the
metal appears white or colorless (silvery)
a. metals are shiny because photons of many wavelengths are
absorbed and then emitted
What is the difference between electron center geometry and
molecular shape?
,- ANSWER-1. they are not always the same
a. to determine the shape of a molecule, consider only the
atoms, not the lone pairs
How do you determine the hybridization of a molecule? -
ANSWER-1. count the
number of atoms connected to the central atom (atoms- not
bonds) and count
the number of lone pairs
attached to it
a. if its 4:
sp^3
b. if its 3:
sp^2
c. if its 2:
sp
Electronegativity - ANSWER-1. ability of an element to attract
electrons to itself in a bond
a. atom with high effective nuclear charge attracts its own
valence electrons strongly and it attracts electrons from other
atoms in bonds
2. Depends on effective nuclear charge
3. trend is same as effective nuclear charge (except for noble
gases)
, a. dec. down a group because atom gets bigger
b. increases across a row because valence electrons are closer
to nucleus
Polar Bonds - ANSWER-1. when 2 atoms of different
electronegativities bond, the electrons are not shared equally
a. results in a bond dipole (bond is polar)
2. molecular shape is important
a. bond dipoles are vector quantities (have magnitude and
direction that need to be taken into account)
Steps to determine molecular polarity - ANSWER-1. draw the
lewis structure
2. determine electron center geometry (gives you bond angle
and hybridization)
3. determine molecular shape
4. determine bond polarities
5. add up bond polarities (take direction into account)
6. determine molecular polarity
Do molecules interact? - ANSWER-Yes
How do molecules interact? What are the effects of these
interactions? - ANSWER-1. the stronger the interactions,
REAL EXAM ELABORATIONS QUESTIONS AND VERIFIED
ANSWERS (100% CORRECTLY SOLVED ) 2025 LATEST
UPDATE !!
How many bonds form between 2 O atoms? - ANSWER-
2 bonds (only
concerned with valence
electrons)
What properties do metals have? -
ANSWER-1. shiny
2. conduct electricity
and heat
a. because electrons can
move freely
3. malleable and
ductile
a. malleable because atoms can move with respect to
one another
,4. may be colored (gold, copper)- silver is colorless (like
most metals)
How does bonding in metals explain their properties? -
ANSWER-1. lots of atomic orbitals combine with each other to
form molecular orbitals (an equal number)
2. As the number of Molecular Orbital's increases, the energy
distance between them decreases and they form bands of
Molecular Orbitals (of almost continuous energy)
3. electrons can move freely between Molecular Orbitals and
over whole system
Why are metals shiny? (properties of metals) - ANSWER-1.
Absorption of a photon will promote an electron to a higher
energy level
2. It immediately falls back down-emitting a photon-the metal
shines
3. the metal interacts with light of many wavelengths, so the
metal appears white or colorless (silvery)
a. metals are shiny because photons of many wavelengths are
absorbed and then emitted
What is the difference between electron center geometry and
molecular shape?
,- ANSWER-1. they are not always the same
a. to determine the shape of a molecule, consider only the
atoms, not the lone pairs
How do you determine the hybridization of a molecule? -
ANSWER-1. count the
number of atoms connected to the central atom (atoms- not
bonds) and count
the number of lone pairs
attached to it
a. if its 4:
sp^3
b. if its 3:
sp^2
c. if its 2:
sp
Electronegativity - ANSWER-1. ability of an element to attract
electrons to itself in a bond
a. atom with high effective nuclear charge attracts its own
valence electrons strongly and it attracts electrons from other
atoms in bonds
2. Depends on effective nuclear charge
3. trend is same as effective nuclear charge (except for noble
gases)
, a. dec. down a group because atom gets bigger
b. increases across a row because valence electrons are closer
to nucleus
Polar Bonds - ANSWER-1. when 2 atoms of different
electronegativities bond, the electrons are not shared equally
a. results in a bond dipole (bond is polar)
2. molecular shape is important
a. bond dipoles are vector quantities (have magnitude and
direction that need to be taken into account)
Steps to determine molecular polarity - ANSWER-1. draw the
lewis structure
2. determine electron center geometry (gives you bond angle
and hybridization)
3. determine molecular shape
4. determine bond polarities
5. add up bond polarities (take direction into account)
6. determine molecular polarity
Do molecules interact? - ANSWER-Yes
How do molecules interact? What are the effects of these
interactions? - ANSWER-1. the stronger the interactions,
