SCH4U - Chemistry 12 (2024-25) - A

Summary

• Electronegativity (EN) is the ability of an atom to attract shared electrons
• The difference in electronegativity (∆EN) between 2 bonded atoms determines the nature of the bond 
• ∆EN > 1.7 = Ionic bond
• ∆EN < 0.5 = non-polar covalent bond
• 0.5 < ∆EN < 1.7 = polar covalent bond
• When there is a difference in electronegativity between 2 bonded atoms, the difference in polarity is called a dipole
• Polarity has substantial effects on the properties of a molecule
• Polar molecules display distinct characteristics compared to non-polar molecules
• Polyatomic molecules can be polar or non-polar depending on the polarity of the bonds within the molecule and the net dipole of the entire molecule
• To determine molecular polarity, we require Lewis Structures, electronegativity values and VSEPR theory