Materials Science And Engineering Exam 1
Study online at https://quizlet.com/_14o52a
1. E0 -Bonding Energy, or the energy required to separate these two atoms to an infinite
separation.
2. Ionic Bonding -Bond between metallic and non-metallic elements.
-Between positive and negative ions.
3. Covalent Bond- -Two electrons shared by two atoms.
ing -Between nonmetals.
4. Metallic Bonding -Net positive ion cores float in a sea of electrons.
5. Dipoles -Positive and negative ends found in polar molecules.
6. Crystalline -Material in which the atoms are situated in a repeating or periodic array over large
atomic distances.
7. Crystal Structure -The manner in which atoms, ions, or molecules are spatially arranged
8. Lattice -Three-dimensional array of points coinciding with atom positions.
9. Unit Cell -A small representation of atomic crystal structure.
10. Face-Centered -Atoms located at each of the corners and the centers of all the cube faces.
Cubic (FCC) -a=2R(2)^1/2
11. Atomic Packing -The sum of the sphere volumes of all atoms within a unit cell divided by the total
Factor (APF) unit cell volume
-FCC and HCP APF: 0.74
-BCC APF: 0.68
12. Body-Centered -Atoms located at all eight corners with one atom in the middle.
Cubic -a=4R/(3)^1/2
13. Theoretical Den- -ρ=nA/VcNa
sity ρ: density (g/cm^3)
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, Materials Science And Engineering Exam 1
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n: number of atoms in unit cell
A: atomic weight (g/mol)
Vc: volume of unit cell (cm^3)
Na: Avogandro's number (6.022x10^23 atoms/mol)
14. Polymorphism -Materials with more than one crystal structure.
-Called allotropy in elemental solids.
15. Lattice Parame- -a,b, and c of unit cell
ters
16. Linear Density -number of atoms per unit length whose centers lie on the direction vector for a
specific crystallographic direction.
-LD= (number of atoms centered on direction vector)/(length of direction vector)
17. Planar Density -number of atoms per unit area that are centered on a particular crystallographic
plane.
-PD= (number of atoms centered on a plane)/(area of plane)
18. Single Crystal -When the periodic and repeated arrangement of atoms is perfect or extends
throughout the entirety of the specimen without interruption.
19. Polycrystalline -Solids composed of a collection of many small crystals or grains.
20. Anisotropic -Values such as variance of atomic or ionic spacing depends on the direction being
measured within the material.
21. Isotropic -Solids in which the properties being measured are independent of the direction
of measurement.
22. Diffraction -Occurs when a wave encounters a series of regularly spaced obstacles that (1)
are capable of scattering the wave, and (2) have spacings that are comparable in
magnitude to the wavelength.
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Study online at https://quizlet.com/_14o52a
1. E0 -Bonding Energy, or the energy required to separate these two atoms to an infinite
separation.
2. Ionic Bonding -Bond between metallic and non-metallic elements.
-Between positive and negative ions.
3. Covalent Bond- -Two electrons shared by two atoms.
ing -Between nonmetals.
4. Metallic Bonding -Net positive ion cores float in a sea of electrons.
5. Dipoles -Positive and negative ends found in polar molecules.
6. Crystalline -Material in which the atoms are situated in a repeating or periodic array over large
atomic distances.
7. Crystal Structure -The manner in which atoms, ions, or molecules are spatially arranged
8. Lattice -Three-dimensional array of points coinciding with atom positions.
9. Unit Cell -A small representation of atomic crystal structure.
10. Face-Centered -Atoms located at each of the corners and the centers of all the cube faces.
Cubic (FCC) -a=2R(2)^1/2
11. Atomic Packing -The sum of the sphere volumes of all atoms within a unit cell divided by the total
Factor (APF) unit cell volume
-FCC and HCP APF: 0.74
-BCC APF: 0.68
12. Body-Centered -Atoms located at all eight corners with one atom in the middle.
Cubic -a=4R/(3)^1/2
13. Theoretical Den- -ρ=nA/VcNa
sity ρ: density (g/cm^3)
1/6
, Materials Science And Engineering Exam 1
Study online at https://quizlet.com/_14o52a
n: number of atoms in unit cell
A: atomic weight (g/mol)
Vc: volume of unit cell (cm^3)
Na: Avogandro's number (6.022x10^23 atoms/mol)
14. Polymorphism -Materials with more than one crystal structure.
-Called allotropy in elemental solids.
15. Lattice Parame- -a,b, and c of unit cell
ters
16. Linear Density -number of atoms per unit length whose centers lie on the direction vector for a
specific crystallographic direction.
-LD= (number of atoms centered on direction vector)/(length of direction vector)
17. Planar Density -number of atoms per unit area that are centered on a particular crystallographic
plane.
-PD= (number of atoms centered on a plane)/(area of plane)
18. Single Crystal -When the periodic and repeated arrangement of atoms is perfect or extends
throughout the entirety of the specimen without interruption.
19. Polycrystalline -Solids composed of a collection of many small crystals or grains.
20. Anisotropic -Values such as variance of atomic or ionic spacing depends on the direction being
measured within the material.
21. Isotropic -Solids in which the properties being measured are independent of the direction
of measurement.
22. Diffraction -Occurs when a wave encounters a series of regularly spaced obstacles that (1)
are capable of scattering the wave, and (2) have spacings that are comparable in
magnitude to the wavelength.
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