(3Q) Solids Flashcards
Atoms or molecules have no long range order. Glass, rubber, many
plastics
Amorphous solids
Atoms or molecules are arranged in a well-ordered three dimensional array
Crystalline Solids
are composed of huge number of small crystals with definite geometric shape that makes them RIGID and INCOMPRESSIBLE.
Crystalline Solids
Why are Crystalline Solids considered true solids?
sharp melting point and definite heat of fusion
basic repeating structural unit of crystalline solids
unit cell
atoms or molecules are represented by each sphere and are identically arranged are called?
lattice point
This unit cell has EQUAL edge lengths and angles, and the atoms are located at the corners of the cube and at the center of each face.
Cubic
3 types of cubic unit cells
simple cubic, body-centered cubic, and face-centered cubic.
This unit cell has TWO different edge lengths and EQUAL angles, with the atoms located at the corners of the parallelepiped.
Tetragonal
This unit cell has THREE different edge lengths and EQUAL angles, with the atoms located at the corners of the parallelepiped.
Orthorhombic
This unit cell has THREE different edge lengths and TWO different angles, with the atoms located at the corners of the parallelepiped
Monoclinic
This unit cell has THREE different edge lengths and THREE different angles, with the atoms located at the corners of the parallelepiped
Triclinic
This unit cell has EQUAL edge lengths and angles, but the parallelogram faces are not perpendicular to each other.
Rhombohedral
This unit cell has EQUAL edge lengths and angles, but the atoms are located at the corners of a hexagon, and the top and bottom faces are hexagons as well
Hexagonal
- Held together by weak IMFs
- Fairly low melting points
Molecular Solids
- Held together by strong Coulombic forces (ionic bonds)
- Fairly high melting points
Ionic Solids
- Held together by very weak dispersion forces
- Very lo melting points
Non Bonding Atomic Solids (solid noble gases
- Held together by interaction of metal cation with electron sea
- Melting points vary
Metallic Atomic Solids
- Held together by covalent bonds between composite units (may have weak IMFs within the structure)
- Very hi melting points
- Function giant molecules
ATOMIC SOLIDS
composed of charged particles where the exact arrangement of ions in a lattice varies. Built electrostatic interaction is strong due to ions. Hard solid
Ionic Crystal
held together by electrostatic force between cations and delocalized electrons. Good conductor of heat and electricity. Dense. Lustrous
Metallic Crystal
lattice points are occupied by molecules and the attractive forces built between the molecules is LDF or Hydrogen bonding
Molecular Crystal
Sulfur Dioxide (SO2), Iodine (I2), naphthalene (C10H8), Sugar
Molecular Crystal
The atoms in this type of crystals are bonded covalently. Very high melting point. And because of the strength of the forces, poor conductor of electricity.
Covalent Crystal
Chemical Nature of Amorphous
Isotropic
Chemical Nature of Crystalline
Anisotropic