7.6 Molecular Structure and Polarity

Explain why the HOH molecule is bent, whereas the HBeH molecule is linear.

Explain the difference between electron-pair geometry and molecular structure.

Explain how a molecule that contains polar bonds can be nonpolar.

Predict the electron pair geometry and the molecular structure of each of the following molecules or ions:

(a) SF₆

(b) PCl₅

(c) BeH₂

(d) $\text{CH}_{3} ^{+}$

What are the electron-pair geometry and the molecular structure of each of the following molecules or ions?

(a) ClF₅

(b) $\text{ClO}_{2} ^{−}$

(c) $\text{TeCl}_{4} ^{\text{2}−}$

(d) PCl₃

(e) SeF₄

(f) $\text{PH}_{2} ^{−}$

Identify the electron pair geometry and the molecular structure of each of the following molecules:

(a) ClNO (N is the central atom)

(b) CS₂

(c) Cl₂CO (C is the central atom)

(d) Cl₂SO (S is the central atom)

(e) SO₂F₂ (S is the central atom)

(f) XeO₂F₂ (Xe is the central atom)

(g) $\text{ClOF}_{2} ^{+}$ (Cl is the central atom)

Which of the following molecules and ions contain polar bonds? Which of these molecules and ions have dipole moments?

(a) ClF₅

(b) $\text{ClO}_{2} ^{−}$

(c) $\text{TeCl}_{4} ^{\text{2}−}$

(d) PCl₃

(e) SeF₄

(f) $\text{PH}_{2} ^{−}$

(g) XeF₂

Which of the following molecules have dipole moments?

(a) CS₂

(b) SeS₂

(c) CCl₂F₂

(d) PCl₃ (P is the central atom)

(e) ClNO (N is the central atom)

The molecule XF₃ has a dipole moment. Is X boron or phosphorus?

Is the Cl₂BBCl₂ molecule polar or nonpolar?

Describe the molecular structure around the indicated atom or atoms:

(a) the sulfur atom in sulfuric acid, H₂SO₄ [(HO)₂SO₂]

(b) the chlorine atom in chloric acid, HClO₃ [HOClO₂]

(c) the oxygen atom in hydrogen peroxide, HOOH

(d) the nitrogen atom in nitric acid, HNO₃ [HONO₂]

(e) the oxygen atom in the OH group in nitric acid, HNO₃ [HONO₂]

(f) the central oxygen atom in the ozone molecule, O₃

(g) e…

Use the simulation to perform the following exercises for a real molecule. You may need to rotate the molecules in three dimensions to see certain dipoles.

(a) Sketch the bond dipoles and molecular dipole (if any) for O_3. Explain your observations.

(b) Look at the bond dipoles for NH₃. Use these dipoles to predict whether N or H is more electronegative.

(c) Predict whether there should be a molecu…

Use the Molecule Shape simulator to explore real molecules. On the Real Molecules tab, select H₂O. Switch between the “real” and “model” modes. Explain the difference observed.