INTERMOLECULAR and INTRAMOLECULAR FORCES Flashcards
a type of interaction between atoms that result in atoms staying close together
bond
two or more atoms held together by a covalent bond
molecule
forces of attraction within a molecule.
intramolecular
forces of attraction between molecules in a compound.
intermolecular
attraction of an atom for electrons
electronegativity
Example of a very electronegative atom:
oxygen
responsible for interactions within a molecule , such as covalent and ionic bonds.
influence the properties of solids and liquids.
pertains to forces that hold individual particles such as atoms, molecules or ions together.
The intramolecular forces of attraction
Acceptor “stealer” of electron becomes negativity charged
(anion = negative ion)
Donor of electron becomes positively charged
(cation = positive ion)
If two atoms with very large differences in electronegativity get together, one of atom could take away an electron from the other
intramolecular: ionic
forms from an attraction between an anion and cation
ionic bond
Ionic compounds are formed by ionic bonds
true
Salt crystals have a 3D lattice because of +/- attractions
true
forms when atoms share electrons
covalent bond
intramolecular bonds:
ionic and covalent bonds
covalent bonds:
non polar and polar
atoms have the same electronegativity
electrons are equally shared
e.g. H2
Nonpolar covalent bond
atoms have slight differences in electronegativity
electrons are unequally shared
e.g. HCl
Polar covalent bond
Polarity dependent on the polarity of the bond AND the molecular SHAPE
true
There are several types of intermolecular forces of attraction. They are collectively known as the…
van der Waals forces, after the Dutch Physicist Johannes Diderik van der Waals (1837-1923) who investigated the weak forces between molecules.
Named after the German born physicist Fritz London, this the weakest among the intermolecular forces. This dispersion force is caused by Polarization, or the distortion of the electron cloud brought about by the presence of a highly charged particle.
Exists between all molecules
Weak force, due to instantaneous dipoles
examples: Carbon dioxide ( CO2 ) Ethanol (CH3CH2OH) Hydrogen (H2) Oxygen (O2) Nitrogen (N2) Xenon (Xe) Argon (Ar)
london dispersion force
This is an intermolecular force of attraction that occurs between partially positive and partially negative ends. This interaction is observed in polar covalent molecules such as amino acids.
Exists between polar molecules
Due to permanent dipoles
Examples:
Sulfur dioxide ((SO2)
Hydrochloric acid (HCl)
Nitric Acid (NH3))
Trichloromethane (CHCl3)
Dipole-dipole Interaction
Strong force (just a very strong dipole-dipole)
Between a polar molecule with an H-atom and a polar molecule with an electronegative atom (usually O, N or F)
Hydrogen Bonding
This arises from the interaction between an ion and a polar molecule. If the molecule is anion, it will be attracted to the partially positive end of the polar molecule, however, if the molecule is a cation, it will be attracted to the partially negative end of the polar molecule.
Dipole is attracted to an oppositely charged ion
When ionic compounds dissolve in water, water molecules surround the ion and remove it from the crystal lattice structure (hydration shell)
Examples:
Calcium chloride (CaCl2)
Sodium chloride (NaCl)
Potassium chloride (KCl)
Ion-dipole interaction
