M1-Lecture7_default

Molecular Shape and Polarity Overview: Molecular shapes impact reactivity and solubility.VSEPR Theory: Predict shape by drawing Lewis structures, counting groups (bonds + lone pairs), and determining geometry.Molecular Shapes:

• 2 Groups: Linear, 180° (e.g., CO2)

• 3 Groups: Trigonal planar, 120° (e.g., carbonate); Trigonal pyramidal (<120°, e.g., SO2)

• 4 Groups: Tetrahedral, 109.5° (e.g., CH4); Trigonal pyramidal (~107°, e.g., NH3); Bent (<109.5°, e.g., H2O)

• 5 Groups: Trigonal bipyramidal, 90°/120° (e.g., PCl5)

• 6 Groups: Octahedral, 90°Polarity: Polar molecules have a net dipole (e.g., water), nonpolar do not (e.g., CO2).Intermolecular Forces:

• Hydrogen Bonds: Strong (N, O, F)

• Dipole-Dipole: In polar molecules

• Induced Dipole: Temporary (London dispersion)Summary: Use VSEPR for shapes and polarity assessment.