chemical bonding Flashcards
what types of bonds do diatomic elements make?
pure covalent/ non-polar-covalent
what type of model in metallic bonding?
sea of electrons (free electron model)
conductivity, thermal conductivity and hardness…
increase moving across a period
structure of ionic bond
lattice (crystal)
EN for ionic bonds
Delta EN > 1.7
are ionic bonds brittle or soft?
brittle
define intramolecular forces
forces within molecule/element interaction
Define intermolecular forces
forces between molecules
do covalent bonds conduct electricity?
no with the exception of acids and bases
EN for polar
EN = 0.5 - 1.7
EN for non-polar
EN < 0.5
when does the central atom have more than 8 valence electrons?
PCl5 and XeF4-
when does the central atom have less than 8 valence electrons?
BH3-
when does a molecule contain an odd number of non-bonding electrons?
NO
what is a cordinate covalent bond?
when both electrons in the bond are donated by the same atom
what are the 4 intramolecular forces?
- London dispersion
- dipole-dipole
- hydrogen bond
- electrostatic forces
what bonds have London dispersion forces?
diatomic or non-polar covalent
what bonds have dipole-dipole forces?
polar covalent bonds with partial charge change
what elements create hydrogen bond forces when combined with hydrogen?
oxygen, nitrogen or fluorine
what type of force is hydrogen bonds?
special dipole-dipole
what bonds have electrostatic forces?
ionic bonds
how do you find the bond type?
change in electronegativity
how do you find the type of intramolecular forces?
looking at the type of bond
non polar or polar molecule: linear diatomic?
non-polar
non polar or polar molecule: linear - two different elements?
polar
non polar or polar molecule: linear - X-A-X format?
non-polar
non polar or polar molecule: bent/angular with unshared pairs?
polar
non polar or polar molecule: trigonal planar?
non-polar
non polar or polar molecule: trigonal pyramidal?
polar
non polar or polar molecule: tetrahedral?
non-polar
how to tell if vsepr is non-polar or polar?
if E is not 0 it is polar
ionic bond melting/boiling point
high
metallic atom melting/boiling point
high
non-polar covalent melting/boiling point
low
polar molecules melting/boiling point
low
covalent networks boiling/melting point
very high
ionic electrical conductivity
good when dissolved in water or melted
metallic electrical conductivity
great in solid and liquid
non-polar covalent electrical conductivity
poor
polar covalent molecule electrical conductivity
poor
covalent network electrical conductivity
poor - graphite is an exception
ionic thermal conductivity
poor
Metallic Thermal Conductivity
good
non-polar Thermal Conductivity
poor
polar Thermal Conductivity
poor
covalent networks thermal conductivity
poor
ionic state at room temperature
solid
metallic state at room temperature
solid to liquid
non-polar state at room temperature
solid, liquid or gas
polar state at room temperature
solid, liquid or gas
covalent networks state at room temperature
solid
intramolecular forces from greatest to weakest
electrostatic, hydrogen bonding, dipole-dipole, London dispersion
why do different compounds have different boiling points?
it depends on the intramolecular forces
how do intramolecular forces affect boiling points?
the stronger the force, the higher the boiling point
Why are ionic compounds brittle?
Ionic compounds are brittle due to the strong bond between the positive and negative ions that make up the molecules. Applying pressure shifts the alignment of the ions and results in brittleness.
