MTL 200 Need to Know Exam
Questions & Answers (Grade 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
,MTL 200 Need to Know Exam
Questions & Answers (Grade A+)
What is the difference between directional and nondirectional
bonding? -
correct answer ✅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? -
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
,MTL 200 Need to Know Exam
Questions & Answers (Grade A+)
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
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%
, MTL 200 Need to Know Exam
Questions & Answers (Grade A+)
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)
t = -(u+v)
w=W
Questions & Answers (Grade 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
,MTL 200 Need to Know Exam
Questions & Answers (Grade A+)
What is the difference between directional and nondirectional
bonding? -
correct answer ✅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? -
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
,MTL 200 Need to Know Exam
Questions & Answers (Grade A+)
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
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%
, MTL 200 Need to Know Exam
Questions & Answers (Grade A+)
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)
t = -(u+v)
w=W
