Polar Bonds

Non-Polar Bonds – covalent bonds that involve exactly equal sharing of the bonded pair(s) of electrons (e.g. Cl with Cl, O with O) or close enough to equal sharing (e.g. C with H) that the shared pair of electrons is equidistant between the two atoms and thus the electronic charge is evenly balanced around all atoms

Polar Bonds – covalent bonds involve uneven sharing of the electron pair or pairs, with one of the atoms (e.g. F, O or Cl) having a slightly stronger attraction for the shared pair of electrons in the bond than the other atom (e.g. C or H). As a result the covalent bonds are closer to that atom with stronger attraction. This gives that atom a slightly negative charge (d-) and the other atom a slightly positive charge (d+)

Polar Molecules – molecules with at least one polar bond and an asymmetrical shape so the dipoles do not cancel

• Oxygen atom has stronger attractions and hydrogen has weaker
• Covalently bonded electrons are closer to oxygen making it slightly negative and the hydrogen atoms slightly positive creating dipoles
• Molecule in asymmetrical shape therefore dipoles do not cancel
• Two polar bonds
• Water is Polar

Non-Polar Molecules – molecules where all bonds are non-polar or with a symmetrical shape causing the dipoles to cancel out

• Carbon and Hydrogen have the same attraction
• Covalently bonded electrons are shared almost equally creating no dipoles
• All bonds are non-polar
• Molecule is in symmetrical shape so if there were polar bonds they would cancel out
• Methane is Non-Polar