Matse 201 Exam 1 With Complete Solutions
Metals
metallic bonding where electrons are delocalized
- dense, stiff, strong, ductile
- high thermal & electrical conductivity
- opaque, reflective
Polymers/plastics
covalent bonding where electrons are shared
- soft, ductile, low strength, low density
- thermal & electrical insulatiors
- optically translucent or transparent
Ceramics
ionic bonding where electrons are donated and received
- oxides, nitrides, carbides
- hard, brittle, refractory, glassy, elastic only
- non-conducting (insulators)
- withstand high temperatures (T>Tm for metals)
Attractive Energy
high Ea --> high MP;
use equation (1/4π*epsilon0*r)(Z₁e)(Z₂e) to determine attractive energy - the higher Z₁*Z₂ is, the
higher the melting point - the higher r is, the lower the melting point
% Ionic Character
use %IC equation to determine how much of ionic bonding there is - what remains is likely covalent
(all compounds have IMFs); Xa & Xb are electroneg values
Single crystalline
long-range order, periodic arrangement, even spacing - all ordered crystal structures can be reduces
to a single unit cell
polycrystalline
some spots of order, some in random spaces
amorphous
complete disorder at long scales
short range order
all materials have bonding at small range order length scales (crystalline materials also have long-
range order)
Types of 2D Lattices
square lattice, rectangular lattice, area centered rectangular lattice, parallelogram lattice, hexagonal
lattice
, primitive lattice
only one lattice point per unit cell (ex: square, parallelogram, rectangular)
7 Crystal Systems
cubic, hexagonal, tetragonal, rhombohedral (trigonal), orthorhombic, monoclinic, triclinic
cubic system
axial relationship: a=b=c;
interaxial angles: α=β=γ=90°
hexagonal system
axial relationship: a=b≠c;
interaxial angles: α=β=90°, γ=120°
tetragonal system
axial relationship: a=b≠c;
interaxial angles: α=β=γ=90°
rhombohedral system (trigonal)
axial relationship: a=b=c;
interaxial angles: α=β=γ≠90°
orthorhombic system
axial relationship: a≠b≠c;
interaxial angles: α=β=γ=90°
monoclinic system
axial relationship: a≠b≠c;
interaxial angles: α=γ=90°≠β
triclinic system
axial relationship: a≠b≠c;
interaxial angles: α≠β≠γ≠90°
Bravais lattices (key ones)
simple cubic, body centered cubic (BCC), face centered cubic (FCC), hexagonal closed packed (HCP),
diamond cubic
Simple Cubic (SC)
1 atom in the unit cell, primitive
BCC
2 atoms in the unit cell, coordination number = 8
Metals
metallic bonding where electrons are delocalized
- dense, stiff, strong, ductile
- high thermal & electrical conductivity
- opaque, reflective
Polymers/plastics
covalent bonding where electrons are shared
- soft, ductile, low strength, low density
- thermal & electrical insulatiors
- optically translucent or transparent
Ceramics
ionic bonding where electrons are donated and received
- oxides, nitrides, carbides
- hard, brittle, refractory, glassy, elastic only
- non-conducting (insulators)
- withstand high temperatures (T>Tm for metals)
Attractive Energy
high Ea --> high MP;
use equation (1/4π*epsilon0*r)(Z₁e)(Z₂e) to determine attractive energy - the higher Z₁*Z₂ is, the
higher the melting point - the higher r is, the lower the melting point
% Ionic Character
use %IC equation to determine how much of ionic bonding there is - what remains is likely covalent
(all compounds have IMFs); Xa & Xb are electroneg values
Single crystalline
long-range order, periodic arrangement, even spacing - all ordered crystal structures can be reduces
to a single unit cell
polycrystalline
some spots of order, some in random spaces
amorphous
complete disorder at long scales
short range order
all materials have bonding at small range order length scales (crystalline materials also have long-
range order)
Types of 2D Lattices
square lattice, rectangular lattice, area centered rectangular lattice, parallelogram lattice, hexagonal
lattice
, primitive lattice
only one lattice point per unit cell (ex: square, parallelogram, rectangular)
7 Crystal Systems
cubic, hexagonal, tetragonal, rhombohedral (trigonal), orthorhombic, monoclinic, triclinic
cubic system
axial relationship: a=b=c;
interaxial angles: α=β=γ=90°
hexagonal system
axial relationship: a=b≠c;
interaxial angles: α=β=90°, γ=120°
tetragonal system
axial relationship: a=b≠c;
interaxial angles: α=β=γ=90°
rhombohedral system (trigonal)
axial relationship: a=b=c;
interaxial angles: α=β=γ≠90°
orthorhombic system
axial relationship: a≠b≠c;
interaxial angles: α=β=γ=90°
monoclinic system
axial relationship: a≠b≠c;
interaxial angles: α=γ=90°≠β
triclinic system
axial relationship: a≠b≠c;
interaxial angles: α≠β≠γ≠90°
Bravais lattices (key ones)
simple cubic, body centered cubic (BCC), face centered cubic (FCC), hexagonal closed packed (HCP),
diamond cubic
Simple Cubic (SC)
1 atom in the unit cell, primitive
BCC
2 atoms in the unit cell, coordination number = 8
