Long test Flashcards
forces exist between molecules
Intermolecular Forces
forces exist
within molecules and hold the atoms in a given molecule together.
Intramolecular Forces
Intermolecular forces (IMF) are _______________________
arising from charge-charge interactions between molecules.
electrostatic attractions
The strength of the intermolecular force is influenced by
the
distance of separation between molecules.
First who introduced the
Intermolecular forces.
Did NOT develop the theory on the
different types of intermolecular but
the first one who postulated the
forces during the development of his
theory on the behaviour of real gases
(1873).
Johannes Diderik van der Waals
+ The strongest intermolecular force. It exists
between oppositely charged ions.
+ Occurs between ionic compounds.
++ Most interaction is strong and compounds
which have them have high melting and boiling
points.
+ is inversely
proportional to the square of distance between the
ions.
Ion-Ion Interaction
+is an attractive force that
results from the electrostatic attraction between
an ion and a neutral molecule that has a dipole.
+ Occurs between a fully charged ion and
partially charged dipole.
+ Its attractions become stronger as either the
charge on the ion increases, or the magnitude of
the dipole of the polar molecule increases.
Ion-Dipole Interaction
+ is a relatively strong force
of attraction between molecules, and
considerable energy is required to break
hydrogen bonds.
+ A special kind of dipole-dipole interaction
that occurs specifically between a hydrogen
atom bonded to either an oxygen, nitrogen, or
fluorine atom.
+ Responsible for the unusually high boiling
point and melting point of water.
Hydrogen bonding
+ forces occur when the partially
positively charged part of a molecule interacts
with the partially negatively charged part of the
neighboring molecule.
+ Interaction is effective over a very short
range.
+ The strength of the interaction is inversely
proportional to distance raised to the fourth
power.
Dipole-Dipole Interaction
+ The weakest of the intermolecular forces and exist
between all types of molecules.
+ Formed due to the attraction between the positively
charged nucleus of an atom with the negatively charged
electron cloud of a nearby atom
+ The more electrons a molecule has, the stronger the
London dispersion forces are.
+ This interaction creates an induced dipole.
+ The strength of dispersion forces is inversely
proportional to distance raised to the 7th power.
London Dispersion Forces
How bond strengths affect Physical Properties of
Substances
+ The physical properties of biological substances depend on the intermolecular
forces present.
- The sequence of strength from strongest to weakest force is ion-ion > ion-dipole >
hydrogen bonding > dipole-dipole > London forces.
+ When the strength of forces decreases, so do the melting points, boiling points,
and solubility in water. The vapor pressure and the solubility in nonpolar solvents
increases.
+ When the strength of forces increases, it will result higher melting or boiling
points, which require breaking molecules apart. Higher intermolecular forces lead to
a higher freezing point.
+ exist WITHIN molecules.
+ It hold the atoms in a given molecule together.
+ The forces that keep a molecule intact; a change in the state of a substance does
not affect intramolecular interactions.
+ are many times stronger than intermolecular forces of
attraction.
Intramolecular Forces
+ Ionic bond is formed by the complete transfer of valence electron(s)
between atoms.
+ It is a type of chemical bond that generates two oppositely charged ions.
+ the metal loses electrons to become a positively charged
cation, whereas the nonmetal accepts those electrons to become a negatively
charged anion.
Ionic Bond
is formed between atoms that have similar
electronegativities—the affinity or desire for electrons.
+ Both atoms have similar affinity for electrons and neither has a tendency
to donate them, they share electrons in order to achieve octet configuration
and become more stable.
Covalent Bond
+ is formed via the attraction of
the mobile electrons—referred to as sea of
electrons—and the fixed positively charged
metal ions.
+ Occurs between atoms of metals, in which
the valence electrons are free to move through
the lattice.
+ are present in samples of
pure elemental metals, such as gold or
aluminum, or alloys, like brass or bronze.
Metallic bonds
INTRAMOLECULAR FORCES
+ Bonding Forces
+ Exist WITHIN Molecules
+ Influence Chemical Properties
Between metals and non-metals
involving ions.
IONIC
Between nonmetals and
nonmetals.
COVALENT
