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MTL 200 Need to Know Questions and
Correct Answers/ Latest Update / Already
Graded
What is an isotope?
Ans: Atoms of the same element that have different numbers
of neutrons
What is the Pauli Exclusion Principle?
Ans: each electron state can hold no more than two electrons
which must have opposite signs
What is the Stable Electron Configuration?
Ans: the state within the outermost shell completely filled (ex.
inert gases: He, Ne, Ar, etc)
What is bonding energy?
Ans: 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?
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Ans: Nondirectional: ionic bonding, metallic bonding
Directional: covalent bonding
What is the difference between directional and nondirectional
bonding?
Ans: Nondirectional: magnitude of the bond is equal in all
directions around an ion
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?
Ans: a = unit cell edge length
R = atomic radius
a = 2Rsqrt(2)
How many atoms are in the FCC structure?
Ans: 4 atoms
What is the relationship between the unit cell edge length and the
atomic radius for BCC crystal structures?
Ans: a = (4R)/sqrt(3)
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How many atoms are in the BCC structure?
Ans: 2 atoms
What is the relationship between the unit cell edge length and the
atomic radius for HCP crystal structures?
Ans: a = 2R
How many atoms are in the HCP structure?
Ans: 6 atoms
What is the formula for volume of HCP unit cell in terms of a and c?
Ans: V = (3ca^2sqrt(3))/2
What are the coordination numbers of FCC, BCC, and HCP structures?
Ans: FCC: 12
BCC: 8
HCP: 12
What are the APF of FCC, BCC, and HCP structures?
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Ans: 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?
Ans: V=4*(4/3)(piR^3)
What is polymorphism? What is it called for elements?
Ans: - 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?
Ans: Cubic structures: [UVW]
Hexagonal structures: [uvtw]
Family of equivalent directions: <uvw> <uvtw>
How do you convert [UVW] to [uvtw]?
Ans: u = (1/3)(2U-V)
All rights reserved © 2025/ 2026 |
MTL 200 Need to Know Questions and
Correct Answers/ Latest Update / Already
Graded
What is an isotope?
Ans: Atoms of the same element that have different numbers
of neutrons
What is the Pauli Exclusion Principle?
Ans: each electron state can hold no more than two electrons
which must have opposite signs
What is the Stable Electron Configuration?
Ans: the state within the outermost shell completely filled (ex.
inert gases: He, Ne, Ar, etc)
What is bonding energy?
Ans: 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?
All rights reserved © 2025/ 2026 |
, Page |2
Ans: Nondirectional: ionic bonding, metallic bonding
Directional: covalent bonding
What is the difference between directional and nondirectional
bonding?
Ans: Nondirectional: magnitude of the bond is equal in all
directions around an ion
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?
Ans: a = unit cell edge length
R = atomic radius
a = 2Rsqrt(2)
How many atoms are in the FCC structure?
Ans: 4 atoms
What is the relationship between the unit cell edge length and the
atomic radius for BCC crystal structures?
Ans: a = (4R)/sqrt(3)
All rights reserved © 2025/ 2026 |
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How many atoms are in the BCC structure?
Ans: 2 atoms
What is the relationship between the unit cell edge length and the
atomic radius for HCP crystal structures?
Ans: a = 2R
How many atoms are in the HCP structure?
Ans: 6 atoms
What is the formula for volume of HCP unit cell in terms of a and c?
Ans: V = (3ca^2sqrt(3))/2
What are the coordination numbers of FCC, BCC, and HCP structures?
Ans: FCC: 12
BCC: 8
HCP: 12
What are the APF of FCC, BCC, and HCP structures?
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Ans: 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?
Ans: V=4*(4/3)(piR^3)
What is polymorphism? What is it called for elements?
Ans: - 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?
Ans: Cubic structures: [UVW]
Hexagonal structures: [uvtw]
Family of equivalent directions: <uvw> <uvtw>
How do you convert [UVW] to [uvtw]?
Ans: u = (1/3)(2U-V)
All rights reserved © 2025/ 2026 |
