HybridizationHybridizationPolarityPolarity

Intermolecular ForcesIntermolecular Forces

SCH4U

• Theoretical process involving the mixing of atomic orbitals to create a new set of orbitals that take part in covalent bonding

• Mainly useful for describing the shapes of organic compounds

…helps to explain the molecular shape of CH4

•CH4 is tetrahedral•Bond angle is 109.5o

•WHY?•Answer: Hybridization of carbon's s and p orbitals

Electron Configuration in Carbon

CH4 – hybridization of Carbon

2s orbital + 3 2p orbitals → 4 hybridised sp3 orbitals

sp3 hybridization

Case of H2O Molecule

• H2O is also tetrahedral • sp3 hybridization• Angle less then 109.5 because

lone the two non-bonding pairs remain closer to the oxygen atom, these exert a stronger repulsion against the two covalent bonding pairs, effectively pushing the two hydrogen atoms closer together. The result is a distorted tetrahedral arrangement in which the H—O—H angle is 104.5°

Polarity of Molecules

Using dipole moment vectors

Since there is a resultant dipole vector, the molecule is POLAR

Non-polar molecules

Polar Molecules

Test your skill…

• Polar or non-polar? Draw the structure, determine shape and use dipole vectors to determine polarity:

• CHCl3 (chloromethane)

• SO3

Answers:

Intermolecular Forces

H-bonding