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MSE Ch 2
Materials Science and Engineering - Atomic Structure
| Term | Definition |
|---|---|
| The structure of materials are examined and described at these 5 levels: ___, ___, ___, ___, ___. | macrostructure, microstructure, nanostructure, atomic arrangements (short-range and long-range), atomic structure |
| ___ deals with sizes between 1,000-100,000 nm. | Macrostructure |
| ___ deals with sizes between 10-1000 nm. | Microstructure |
| ___ deals with sizes between 1-100 nm. | Nanostructure |
| An atomic arrangement that is ___ lacks long-range ordering of atoms. | amorphous |
| An atomic arrangement that is ___ exhibits periodic geometrical arrangements of atoms. | crystalline |
| ___ materials have ONLY short-range atomic arrangements. | Amorphous |
| ___ materials have short-range AND long-range atomic arrangements. | Crystalline |
| The letter ___ denotes electrical charge. | q |
| Each electron and each proton carries q of ___. | 1.6 x 10^-19 coulomb (C) |
| The mass of each proton and neutron is ___. | 1.67 x 10^-24 g |
| The mass of each electron is ___. | 9.11 x 10^-28 g |
| N_A stands for ___. | Avagadro number |
| N_A = ___. | 6.023 x 10^23 atoms/mol |
| When lead-zirconium-titanate (PZT) ions are arranged in a tetragonal or rhombohedral crystals the material is ___. It develops electricity when subjected to ___ or ___. | piezoelectric, pressure, stress |
| The energy level at which electrons belong is called the ___. | quantum number |
| The 4 quantum numbers are ___, ___, ___, & ___. | n, l, m_l, m_s |
| n = ___. | principal quantum number or primary quantum number |
| n refers to the ___, which is the energy level to which an electron belongs. | quantum shell |
| Each electron in a quantum shell is designated by one of four quantum numbers and the letters ___=1, ___=2, ___=3, etc. | K, L, M |
| As the quantum shell number increases, the energy ___. | increases |
| The azimuthal quantum number is designated by the letter ___. | l |
| Each electron in a quantum shell is designated by one of four azimuthal quantum numbers ___, ___, ___, & ___ that represent___. | s, p, d, f, orbitals |
| ___ is the azimuthal quantum number with the lowest energy and ___ has the highest. | s, f |
| The azimuthal quantum number orbital that is shaped like O is ___. | s |
| The azimuthal quantum number orbital that is shaped like 8 is ___. | p |
| The azimuthal quantum number orbital that is shaped like a clover leaf is ___. | d |
| The azimuthal quantum number is also called a ___. | subshell |
| If n=1, l=___. If n=2, l=___. (etc.) | 0, 1 |
| The magnetic quantum number is designated by ___ and gives us ___. | m_l, the number of orbitals/subshells in each quantum shell (shell) |
| The formula ___ gives the total number of orbitals for each subshell (l). | 2l + 1 |
| The Pauli exclusion principle specifies that ___. | no more than 2 electrons, with opposing spins, may be present in each orbital |
| Shorthand notation for He is 1s^2. 1=___. s=___. 2=___. | n, subshell, number of electrons |
| Deviations from expected electron structures occur particularly when ___. | atomic number is high |
| Fe has an unfilled ___ level which causes its ___ behavior. | 3d, magnetic |
| The ___ of an atom is the number of electrons that participate in bonding. | valence |
| Electronegativity describes the tendency of an atom to ___ an electron. | gain |
| ___ atoms tend to lose electrons. | Electropositive |
| Engineering is mostly concerned with the following materials: ___, ___, & ___. | polymers, ceramics, metallic materials |
| The primary bond/s is/are ___. | metallic, covalent, ionic |
| The secondary bond/s is/are ___. | van der Waals |
| Primary bonds are achieved when ___. | an atom fills its valence shell |
| In ___ bonds, atoms are more electro___ and donate their valence electrons to form a "sea" of electrons. | metallic, positive |
| Because their valence electrons move freely, most pure metals are good ___. | electrical conductors |
| Under the influence of voltage, metallic valence electrons move, causing ___. | a current that creates a circuit |
| Metallic bonds result in a high/low Young's modulus of elasticity because ___. | high, atoms are close together |
| ___ refers to the ability of materials to be stretched or bent without breaking. | Ductility |
| Metals show good ductility because the bonds are ___. | non-directional |
| Atoms in ___ bonds have a fixed directional relationship with each other and form specific angles. | covalent |
| Covalent bonds are very strong/weak. | strong |
| Covalent bonds generally have high/low melting points. | high |
| If two electrical charges, +q and -q, are separated by a distance d, the dipole moment is defined as ___. | q x d |
| A ___ atom has no dipole moment, but a ___ molecule may. | neutral, neutral |
| A dipole moment is created when ___. | a neutral atom is exposed to an internal or external electrical field |
| Forces created when atoms with dipoles are attracted to each other are called ___. | van der Vaals forces |
| The three types of van der Vaals forces are ___, ___, & ___. | London, Keesom, Debye |
| van der Vaals forces between atoms or molecules that are both induced are called ___. | London |
| van der Vaals forces between atoms or molecules where one is induced and one is permanent are called ___. | Debye |
| van der Vaals forces between atoms or molecules that are both permanent are called ___. | Keesom |
| Hydrogen bonds are ___ bonds. | Keesom |
| ___ temperature is a temperature below which polymers tend to behave as brittle materials (poor ductility). | Glass |
| Glass temperature is denoted with ___. | T_g |
| Polymers are "plasticized" by adding ___ that interact with the long molecules. | shorter polar molecules |
| Plasticizing lowers the T_g and increases ___. | flexibility |
| T or F? Most materials are mixed bonds. | T |
| Intermetallic compounds are generally ___ and ___ bonds. | metallic, ionic |
| The higher the difference between the electronegativities of two metals, the ___(higher/lower) the percentage of ionic bonds there will be. | higher |
| The fraction covalent formula is ___. | e^(-0.25ΔE²) or e^(-0.25(difference in electronegativities)^2) |
| Interatomic spacing (equlibrium distance) between atoms is due to ___. | repulsive and attractive forces |
| Equilibrium separation occurs when ___. | the total interatomic energy (IAE) of the pair of atoms is at a minimum or when no net force is acting to either attract or repel the atoms |
| Interatomic spacing in a solid metal is approximately equal to ___. | the atomic diameter (twice the r) |
| Interatomic spacing in ionically bonded material is approximately equal to ___. | the sum of both r |
| ___ is the minimum energy required to either create or break a bond. | Binding energy |
| Materials with a high binding energy have ___ strength and ___ melting point. | high, high |
| A material that requires greater force to stretch the bond is said to have a high ___. | modulus of elasticity |
| Modulus of elasticity is AKA ___. | Young's modulus |
| The level of stress at which a material begins to deform is known as the ___. | yield strength |
| The formula for the coefficient of thermal expansion is ___. | α=(1/L)(dL/dT) where L=direction and T=temperature |
| CTE is related to the ___. | strength of the bonds |
Created by:
drjolley
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