Chapter 2 Flashcards
Temporary Dipole
Formed when the electrons, which are constantly in motion, are momentarily arranged so as to produce an asymmetric charge distribution.
Hydrogen Bond
Occurs whenever a hydrogen atom can be shared between two strongly electronegative atoms such as N, O, F, or Cl.
Coordination Number
The arrangement of atoms within a solid can be principally characterized by the number of nearest neighbors
Core Electrons
The electrons in the filled shells “below” the valence shell.
Metallic Bonds
Solids composed primarily of electropositive elements containing three or fewer valence electrons are bonded by metallic Bonds
amorphous material
A type of solid that only exhibits short-range order
Arrhenius equation
Reaction rate = C^(-Q/RT) ; where Q is the activation energy, T is absolute gas temperature, R is the gas constant.
atomic scale structure
- The types of atoms present
- The types of bonding between the atoms
- the way the atoms are packed together
bond angles
angles between atoms or molecules that are bonded.
bond energy
measure of the inherent strength of a bond
bond-energy curve
An illustration of the relationship between U and x and is sometimes called the bond energy well
bond-force curve
illustration showing the relationship between competing forces and x
bond length
average center-to-center distance between atoms
coefficient of thermal expansion
Macroscopic property with connection to the bond-energy curve. As temp increases atoms are able to move up the sides of the energy well.
covalent bonds
Form in compounds composed of electronegative elements, especially those with four or more valence electrons.
crosslinks
The primary bonds between rubber chains formed by the opening of the unsaturated double bonds
crystalline materials
A type of solid that exhibits both short-range order and long-range order
ductile
Atoms in a material can slip past one another after impact.
electron affinity
The energy released when an isolated neutral electronegative atom gains an electron.
electron configuration
the distribution of electrons within the permissible energy levels
electronegativity
The relative tendency of that element to gain, or attract, an electron, generally increases as you read the periodic table from left to right.
short-range order
the number and type of nearest neighbors associated with a particular solid structure
Young’s modulus (E)
A measure of the resistance of the material to relative atomic separation (stiffness).
ground state
electrons occupy the lowest energy subshells consistent with the pauli exclusion principle
ionic bond
Bond in a compound containing both electropositive and electronegative elements. This bond involves electron transfer from the electropositve atom to the electronegitive one.
ionization potential
The energy required to remove an electron from an isolated neutral atom
intermetallics
materials made of a mix of metals that usually exhibit either mixed metallic/covalent or mixed metallic/ionic bonds characteristics.
Pauli exclusion principle
states that no two interacting electrons may have the same four quantum numbers.
polymers
many identical units(mers) linked together
quantum number
Valid solutions to the schrodinger equation identified by a set of three integer values (n, l, and m).
thermodynamics
The study of the relationships between the thermal properties of matter and external variables such as pressure, temperature, and composition
thermoplastic polymer
linear polymers that form melts upon heating
thermoset polymer
polymers that do not form a melt
valence electrons
electrons on the outer most shell of an atom
