Midterm 1 Review Flashcards
Metals are characterized by which one of the following bonding types:
(a) covalent
(b) hydrogen
(c) ionic
(d) metallic
(e) van der Waals
Metallic
fill in blank
The nucleus of an atom contains _____ & _______
Protons; Neutrons
An element with electron configuration has how many electrons?
1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6)
18
What is the the electron configuration for an inert gas?
1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(2) 4s^(2)
The electrons that occupy the outermost filled shell are called ________ electrons.
valence
Atomic bonding type in ceramics is: _____ and ________
Ionic; Covalent
Atomic bonding in Semi-metals (metalloids) is:
mixed covalent-metallic
Materials whose constituent particles bound by which type of bond are generally expected to have the highest melting temperature?
ionic
How many atoms are there in the body-centered cubic (BCC) unit cell ?
9
How many atoms are associated (per unit cell) with each face-centered cubic (FCC) unit cell or how many atoms may be assigned to a FCC unit cell?
4
How many atoms are there in a hexagonal close-packed (HCP) unit cell?
17
True or False: The coordination number and the atomic packing factor for the HCP crystal structure are the same as for FCC.
True
Fill in blank with a numerical value
The atomic packing factor (APF) for BCC structure is ____.
0.68
In materials exhibiting mixed bonding, the percent ionic character (%IC) between two elements A and B depends on _________ ________.
electronegative values
Bragg’s law is used to determine:
Inter-planar spacing
The equilibrium number of vacancies, N_v, for a given quantity of material depends or increases with temperature according to :
exponentially
True or False: In metals, there are significantly more vacancies than self-interstitials.
True
True or False: The solute is an element or compound present in the greatest amount.
False
skipped #19 because it contains image
just write “skip”
skip
May have more than 1 answer.
Which of the following statements about crystal structures are true?
(a) metals are almost never in crystal form
(b) amorphous materials do not have long range order
(c) FCC and HCP materials, if made from the same atoms, would have the same density,
(d) BCC and HCP have the same atomic packing factor
A solid-solution alloy is _______
Which of these is a linear defect?
(a) vacancy
(b) interstitual
(c) edge dislocation
(d) substitutional
edge dislocation
True or False: Solid solution are also formed in ceramics
True
The maximum allowable concentration of impurity atoms in interstitual solid solution is:
less than 10%
Which of these defects occur only in ceramics?
a) a screw dislocation
(b) A Schottky defect
(c) edge dislocation
(d) staking faults
True or False: Property values are independent of crystallographic direction of measurement in isotropic materials.
True
What are the three basic categories of materials?
Name the fourth category of materials
1) Metals
2) Ceramics
3) Polymers
4) Composites
Expain the distintive characteristics of each type of material. (From the three basic types of materials)
Give two example for each materials.
Define a unit cell
Explain the difference between a polycrystalline material and a single crystal
Define and describe: theoretical density
Name the factors that determine the theoretical density of a metal
Define and describe: planar density
Define and describe: linear density
