MTL 200 Need to Know Exam Questions
and Answers A
What is an isotope? - Correct answer-Atoms of the same element that have
different numbers of neutrons
What is the Pauli Exclusion Principle? - Correct answer-each electron state can
hold no more than two electrons which must have opposite signs
What is the Stable Electron Configuration? - Correct answer-the state within the
outermost shell completely filled (ex. inert gases: He, Ne, Ar, etc)
What is bonding energy? - Correct answer-the energy required to separate two
atoms that are chemically bonded to an infinite distance (units: kJ/mol or eV/atom)
Which kinds of bonds are nondirectional? Which are directional? - Correct answer-
Nondirectional: ionic bonding, metallic bonding
Directional: covalent bonding
What is the difference between directional and nondirectional bonding? - Correct
answer-Nondirectional: magnitude of the bond is equal in all directions around an
ion
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,Directional: atoms need to be in a specific orientation
What is the relationship between the unit cell edge length and the atomic radius for
FCC crystal structures? - Correct answer-a = unit cell edge length
R = atomic radius
a = 2Rsqrt(2)
How many atoms are in the FCC structure? - Correct answer-4 atoms
What is the relationship between the unit cell edge length and the atomic radius for
BCC crystal structures? - Correct answer-a = (4R)/sqrt(3)
How many atoms are in the BCC structure? - Correct answer-2 atoms
What is the relationship between the unit cell edge length and the atomic radius for
HCP crystal structures? - Correct answer-a = 2R
How many atoms are in the HCP structure? - Correct answer-6 atoms
What is the formula for volume of HCP unit cell in terms of a and c? - Correct
answer-V = (3ca^2sqrt(3))/2
What are the coordination numbers of FCC, BCC, and HCP structures? - Correct
answer-FCC: 12
BCC: 8
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, HCP: 12
What are the APF of FCC, BCC, and HCP structures? - Correct answer-FCC: 0.74
or 74%
BCC: 0.68 or 68%
HCP: 0.74 or 74%
What is the formula for the volume of 4 atoms in FCC? - Correct answer-
V=4*(4/3)(piR^3)
What is polymorphism? What is it called for elements? - Correct answer-- the
phenomenon of a solid material existing in more than one form of crystal structure.
- for elements, it is called allotropy
What coordinate form do you use for crystallographic directions for cubic
structures, hexagonal structures and for a family of equivalent directions? - Correct
answer-Cubic structures: [UVW]
Hexagonal structures: [uvtw]
Family of equivalent directions: <uvw> <uvtw>
How do you convert [UVW] to [uvtw]? - Correct answer-u = (1/3)(2U-V)
v = (1/3)(2V-U)
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and Answers A
What is an isotope? - Correct answer-Atoms of the same element that have
different numbers of neutrons
What is the Pauli Exclusion Principle? - Correct answer-each electron state can
hold no more than two electrons which must have opposite signs
What is the Stable Electron Configuration? - Correct answer-the state within the
outermost shell completely filled (ex. inert gases: He, Ne, Ar, etc)
What is bonding energy? - Correct answer-the energy required to separate two
atoms that are chemically bonded to an infinite distance (units: kJ/mol or eV/atom)
Which kinds of bonds are nondirectional? Which are directional? - Correct answer-
Nondirectional: ionic bonding, metallic bonding
Directional: covalent bonding
What is the difference between directional and nondirectional bonding? - Correct
answer-Nondirectional: magnitude of the bond is equal in all directions around an
ion
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,Directional: atoms need to be in a specific orientation
What is the relationship between the unit cell edge length and the atomic radius for
FCC crystal structures? - Correct answer-a = unit cell edge length
R = atomic radius
a = 2Rsqrt(2)
How many atoms are in the FCC structure? - Correct answer-4 atoms
What is the relationship between the unit cell edge length and the atomic radius for
BCC crystal structures? - Correct answer-a = (4R)/sqrt(3)
How many atoms are in the BCC structure? - Correct answer-2 atoms
What is the relationship between the unit cell edge length and the atomic radius for
HCP crystal structures? - Correct answer-a = 2R
How many atoms are in the HCP structure? - Correct answer-6 atoms
What is the formula for volume of HCP unit cell in terms of a and c? - Correct
answer-V = (3ca^2sqrt(3))/2
What are the coordination numbers of FCC, BCC, and HCP structures? - Correct
answer-FCC: 12
BCC: 8
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, HCP: 12
What are the APF of FCC, BCC, and HCP structures? - Correct answer-FCC: 0.74
or 74%
BCC: 0.68 or 68%
HCP: 0.74 or 74%
What is the formula for the volume of 4 atoms in FCC? - Correct answer-
V=4*(4/3)(piR^3)
What is polymorphism? What is it called for elements? - Correct answer-- the
phenomenon of a solid material existing in more than one form of crystal structure.
- for elements, it is called allotropy
What coordinate form do you use for crystallographic directions for cubic
structures, hexagonal structures and for a family of equivalent directions? - Correct
answer-Cubic structures: [UVW]
Hexagonal structures: [uvtw]
Family of equivalent directions: <uvw> <uvtw>
How do you convert [UVW] to [uvtw]? - Correct answer-u = (1/3)(2U-V)
v = (1/3)(2V-U)
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