Question 1

Which of the following statements best explains why the shape of a molecule is crucial for enzyme action in biological systems?

Accepted Answer

The shape of a molecule allows it to fit specifically into the active site of an enzyme, enabling selective binding and catalysis.

Question 2

According to VSEPR theory, what is the electron-domain geometry and approximate bond angle for a molecule with three electron groups and no lone pairs on the central atom?

Accepted Answer

Trigonal planar, $$120^\circ$$

Question 3

Which of the following molecules is nonpolar, despite having polar bonds?

Accepted Answer

CO$$_2$$

Question 4

What is the molecular geometry and hybridization of the central atom in methane (CH$$_4$$)?

Accepted Answer

Tetrahedral, $$sp^3$$

Question 5

Which of the following best describes the difference between electron-domain geometry and molecular geometry?

Accepted Answer

Electron-domain geometry considers both bonding and lone pairs, while molecular geometry considers only the positions of atoms.

Question 6

A molecule has the formula AX$$_2E$_2. $$What is its molecular geometry and approximate bond angle?

Accepted Answer

Bent, $$\u003c109.5^\circ$$

Question 7

Which hybridization is associated with a central atom that has five electron groups around it?

Accepted Answer

$$sp^3d$

Question 8

In the molecule SF$$_6$$, what is the electron-domain geometry, molecular geometry, and hybridization of the central atom?

Accepted Answer

Octahedral, octahedral, $$d^2sp^3$

Question 9

Which of the following statements about sigma ($$\sigma) $$and pi ($$\pi) $$bonds is correct?

Accepted Answer

A single bond is always a $$\sigma$$ bond.

Question 10

Which of the following molecules has a net dipole moment?

Accepted Answer

H$$_2O$$

Question 11

What is the molecular geometry of PCl$$_5$$ and what are the bond angles between the equatorial and axial positions?

Accepted Answer

Trigonal bipyramidal; $$120^\circ ($$equatorial), $$90^\circ ($$axial-equatorial)

Question 12

Which of the following best explains why lone pairs occupy more space than bonding pairs in VSEPR theory?

Accepted Answer

Lone pairs are not shared between atoms and thus exert greater repulsive force on other electron domains.

Question 13

Which of the following molecules is an example of a geometric (cis-trans) isomer, and why does this isomerism occur?

Accepted Answer

cis-1,2-dichloroethene; because rotation around the double bond is restricted

Question 14

What is the hybridization of the central atom in BF$$_3$$ and what is the geometry of the molecule?

Accepted Answer

$$sp^2$$, trigonal planar

Question 15

Which of the following best describes the bond rotation in single, double, and triple bonds?

Accepted Answer

Single bonds allow free rotation, double and triple bonds restrict rotation due to the presence of $$\pi$$ bonds.

Question 16

A molecule has four electron groups: three bonding pairs and one lone pair. What is its molecular geometry and approximate bond angle?

Accepted Answer

Trigonal pyramidal, $$\u003c109.5^\circ$$

Question 17

Which of the following is a correct statement about the relationship between electronegativity, molecular geometry, and molecular polarity?

Accepted Answer

A molecule with nonpolar bonds is always nonpolar.

Question 18

Which orbitals overlap to form the bonds in BeCl$$_2$$ according to valence bond theory?

Accepted Answer

Cl (3p) and Be (sp)

Question 19

Which of the following molecules has a seesaw molecular geometry?

Accepted Answer

SF$$_4$$

Chemical Bonding Theories: VSEPR, Molecular Geometry, Polarity, and Hybridization

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