Valence shell electron pair repulsion theory (VSEPR)
Predicts the shape and bond angles of molecules
Electrons are negatively charged and will repel other electrons when close to each other
Bonding pairs of electrons will repel other electrons around the central atom forcing the molecule to adopt a shape in which these repulsive forces are minimised
When two atoms in a covalent bond have the same electronegativity the covalent bond is nonpolar
When two atoms in a covalent bond have different electronegativities the covalent bond is polar and the electrons will be drawn towards the more electronegative atom
To determine whether a molecule with more than two different atoms is polar, the polarity of each bond and how the bonds are arranged in the molecule must be considered
Some molecules have polar bonds but are overall not polar because the polar bonds in the molecule are arranged in such way that the individual dipole moments cancel each other out
CH3Cl has four polar covalent bonds which do not cancel each other out causing CH3Cl to be a polar molecule; the overall dipole is towards the electronegative chlorine atom
The strongest form of intermolecular bonding, a type of permanent dipole-dipole bonding
Requires a species with an O, N or F atom bonded to H, where the H becomes highly δ+ and can bond with the lone pair of an O, N or F in another molecule