CEM 141 PRACTICE EXAM QUESTIONS
WITH 100% CORRECT ANSWERS
What is the wavelength of light that has a frequency of 3.0 GHz (3* 10^6 Hz)?
A. 100 m
B. 100 nm
C. 10 cm
D. 3.0 * 10^8 m - Answer-A
What wavelength of light would break a O=O bond (it takes 8.3*10^-19 J to break one
bond)?
A. 240 nm
B. 1.5*10^-15 m
C. 500 nm
D. 10 nm - Answer-A
Atomic absorption spectra are caused by:
A. Photons moving between energy levels in an atom.
B. Electrons moving to lower energy levels and releasing photons of energy equal to the
energy difference between the levels.
C. Electrons moving to higher energy levels and absorbing photons of energy equal to
the energy difference between the levels.
D. Electrons being ejected from the surface of the metal when hit by a photon. -
Answer-C
How many core and valence electrons does carbon have?
A. 6 core, 6 valence
B. 2 core, 4 valence
C. 4 core, 2 valence
D. 10 core, 2 valence - Answer-B
Why do bonds form between atoms?
A. They want to share electrons.
B. They need a full octet.
C. Valence electrons are attracted to a nucleus of another atom.
D. The potential energy is at a minimum. - Answer-C
There are two elements in the second row. How many molecular orbitals would be
generated?
, A. 2
B. 4
C. 5
D. 10 - Answer-D
How many bonds form between two O atoms?
A. 0
B. 1
C. 2
D. 3
E. 4 - Answer-C
What kind of interaction must be overcome in order to melt H?
A. LDF
B. Covalent
C. Metallic
D. LDF and covalent - Answer-A
What kind of interaction must be overcome in order to melt He?
A. LDF
B. Covalent
C. Metallic
D. LDF and covalent - Answer-A
What kind of interaction must be overcome in order to melt Li?
A. LDF
B. Covalent
C. Metallic
D. LDF and covalent - Answer-C
What kind of interaction must be overcome in order to melt C?
A. LDF
B. Covalent
C. Metallic
D. LDF and covalent - Answer-B
Which has a larger atomic radius? Mg or Ar? Why?
A. Mg, because it is a metal.
B. Mg, because its valence electrons are not as strongly attracted towards the nucleus
as those in Ar.
C. Ar, because it is a heavier element.
D. Ar, because it has more electrons and they repel each other. - Answer-B
Out of Na+, Mg2+, Ne, and F- which has the smallest radius?
A. Na+
B. Mg2+
C. Ne
WITH 100% CORRECT ANSWERS
What is the wavelength of light that has a frequency of 3.0 GHz (3* 10^6 Hz)?
A. 100 m
B. 100 nm
C. 10 cm
D. 3.0 * 10^8 m - Answer-A
What wavelength of light would break a O=O bond (it takes 8.3*10^-19 J to break one
bond)?
A. 240 nm
B. 1.5*10^-15 m
C. 500 nm
D. 10 nm - Answer-A
Atomic absorption spectra are caused by:
A. Photons moving between energy levels in an atom.
B. Electrons moving to lower energy levels and releasing photons of energy equal to the
energy difference between the levels.
C. Electrons moving to higher energy levels and absorbing photons of energy equal to
the energy difference between the levels.
D. Electrons being ejected from the surface of the metal when hit by a photon. -
Answer-C
How many core and valence electrons does carbon have?
A. 6 core, 6 valence
B. 2 core, 4 valence
C. 4 core, 2 valence
D. 10 core, 2 valence - Answer-B
Why do bonds form between atoms?
A. They want to share electrons.
B. They need a full octet.
C. Valence electrons are attracted to a nucleus of another atom.
D. The potential energy is at a minimum. - Answer-C
There are two elements in the second row. How many molecular orbitals would be
generated?
, A. 2
B. 4
C. 5
D. 10 - Answer-D
How many bonds form between two O atoms?
A. 0
B. 1
C. 2
D. 3
E. 4 - Answer-C
What kind of interaction must be overcome in order to melt H?
A. LDF
B. Covalent
C. Metallic
D. LDF and covalent - Answer-A
What kind of interaction must be overcome in order to melt He?
A. LDF
B. Covalent
C. Metallic
D. LDF and covalent - Answer-A
What kind of interaction must be overcome in order to melt Li?
A. LDF
B. Covalent
C. Metallic
D. LDF and covalent - Answer-C
What kind of interaction must be overcome in order to melt C?
A. LDF
B. Covalent
C. Metallic
D. LDF and covalent - Answer-B
Which has a larger atomic radius? Mg or Ar? Why?
A. Mg, because it is a metal.
B. Mg, because its valence electrons are not as strongly attracted towards the nucleus
as those in Ar.
C. Ar, because it is a heavier element.
D. Ar, because it has more electrons and they repel each other. - Answer-B
Out of Na+, Mg2+, Ne, and F- which has the smallest radius?
A. Na+
B. Mg2+
C. Ne
