Advanced timed challenge: In an intermolecular forces setting, use London dispersion, dipole-dipole forces, hydrogen bonding, vapor pressure, boiling point, and molecular polarity. Explain how resonance affects the bond lengths in the carbonate ion ($CO_3^{2-}$). State the setup, compute carefully, and interpret the result.

Advanced timed challenge: In an intermolecular forces setting, use London dispersion, dipole-dipole forces, hydrogen bonding, vapor pressure, boiling point, and molecular polarity. Use VSEPR theory to predict the molecular geometry of sulfur tetrafluoride ($SF_4$). Provide a concise written explanation.

Advanced timed challenge: In an intermolecular forces setting, use London dispersion, dipole-dipole forces, hydrogen bonding, vapor pressure, boiling point, and molecular polarity. Determine which bond is more polar: C-F or C-O. Justify using electronegativity trends. State the setup, compute carefully, and interpret the result.

Advanced timed challenge: In an intermolecular forces setting, use London dispersion, dipole-dipole forces, hydrogen bonding, vapor pressure, boiling point, and molecular polarity. Compare the properties of NaCl and diamond to distinguish between ionic and covalent network solids. Provide a concise written explanation.

Advanced timed challenge: In an intermolecular forces setting, use London dispersion, dipole-dipole forces, hydrogen bonding, vapor pressure, boiling point, and molecular polarity. Draw the Lewis structure for the nitrate ion ($NO_3^-$) and specify the number of lone pairs on the central atom. State the setup, compute carefully, and interpret the result.

Advanced timed challenge: In an intermolecular forces setting, use London dispersion, dipole-dipole forces, hydrogen bonding, vapor pressure, boiling point, and molecular polarity. Calculate the formal charge of the central oxygen atom in ozone ($O_3$). Provide a concise written explanation.