MTL 200 NEED TO KNOW EXAM QUESTIONS WITH 100% CORRECT ANSWERS LATEST VERSION 2025/2026.

MTL 200 NEED TO KNOW EXAM
QUESTIONS WITH 100% CORRECT
ANSWERS LATEST VERSION 2025/2026.




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? - 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


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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? - 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)



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? - ANS FCC: 0.74 or 74%
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, 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)

v = (1/3)(2V-U)

t = -(u+v)

w=W



What is the formula for linear density (LD)? - ANS LD = (# of atoms centered on a direction
vector)/(length of direction vector)



What kind of brackets are used for linear? ( ) or [ ]? - ANS []



What is the formula for planar density? (PD) - ANS PD = (# of atoms centered on a
plane)/(area of a plane)



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