ENGN1215 Study Guide - Quiz Guide: Atomic Packing Factor, Miller Index, Allotropy
Atomic number
Number of protons in an atom
Van der Waals
bonding
General term used to define the attraction of intermolecular forces between
molecules
Dipole
Attractive force between the positive end of one polar molecule and the negative
end of another
Ionic bonding
intramolecular bonding, electrostatic attraction between oppositely charged ions
Quantum
number
Every electron is characterized by four quantum numbers and hence, its
properties
Electronegativity
The tendency of an atom to accept electrons
Ion
A charge particle, usually an atom that has lost or gained electrons
Valency
Combining power with other atoms
Subshell
Location of electron within a shell number dictated by s, p,d
Positional
equilibrium
Interatomic force (force that holds molecules together) =0
Periodic table
Arrangement of all elements by valence electrons and shell number
Crystalline
materials
Atoms pack in periodic 3D arrays (typical of metals, ceramics, some polymers)
Miller indices
The way by which a crytallographic plane can be identified in a lattice with an
arbitrary coordinate system
1. Plane cannot pass through origin ( redefine if necessary)
2. Intersect points of the plane with x, y, z axes (if parallel then infinity)
3. A,b,c reciprocated (infinity →0)
4. Factored up to whole numbers
5. Denoted (h,k,l)
Allotropy
(polymorphism)
Different physical forms that an element can exist in
Amorphous
Non crystalline structure (complex structures, rapid cooling)
APF
(Atomic packing factor): fraction of solid sphere volume in unit cell —> volume of
atoms in a unit cell/ total unit cell volume
Lattice
parameters
Physical dimension of unit cells in a crystal lattice (a, b, c- , , γ)
Close packed
plane
The crystalline plane that contains the highest density of atoms to area
Crystal structure
Described by both the geometry of and atomic arrangements with the unit cell e.g.
FCC or BCC
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Crystal system
Described only in terms of the unit cell geometry
Bragg’s Law
When an x ray hits a crystal the refracted ray satisfies Bragg’s law
BCC (Body
centered cubic)
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Document Summary
Atomic number number of protons in an atom. General term used to define the attraction of intermolecular forces between molecules. Attractive force between the positive end of one polar molecule and the negative end of another intramolecular bonding, electrostatic attraction between oppositely charged ions. Electronegativity the tendency of an atom to accept electrons. Every electron is characterized by four quantum numbers and hence, its properties. A charge particle, usually an atom that has lost or gained electrons. Location of electron within a shell number dictated by s, p,d. Interatomic force (force that holds molecules together) =0. Arrangement of all elements by valence electrons and shell number. Atoms pack in periodic 3d arrays (typical of metals, ceramics, some polymers) Different physical forms that an element can exist in. Non crystalline structure (complex structures, rapid cooling) atoms in a unit cell/ total unit cell volume (atomic packing factor): fraction of solid sphere volume in unit cell > volume of.
