Question 1

Which of the following best explains why morphine can bind to opioid receptors in the human body?

Accepted Answer

Morphine has a similar molecular shape to endorphins, allowing it to fit into the receptor's active site.

Question 2

According to VSEPR theory, what is the electron geometry around a central atom with three electron groups and no lone pairs?

Accepted Answer

Trigonal planar

Question 3

A molecule has the Lewis structure shown below. What is the predicted bond angle around the central atom?

$$\mathrm{Cl-Be-Cl}$$

Accepted Answer

$$180^\circ$$

Question 4

Which of the following molecules is predicted to have a trigonal planar molecular geometry?

Accepted Answer

BF$$_3$$

Question 5

Formaldehyde (CH$$_2O) $$has three electron groups around the central carbon atom. What is the expected bond angle between the hydrogen atoms?

Accepted Answer

Slightly less than $$120^\circ$$ due to the presence of a double bond

Question 6

Which of the following statements about lone pairs and bond angles is correct?

Accepted Answer

Lone pairs exert greater repulsion than bonding pairs, decreasing bond angles from the ideal geometry.

Question 7

What is the molecular geometry of a molecule with four electron groups around the central atom, two of which are lone pairs?

Accepted Answer

Bent

Question 8

A central atom has five electron groups: three bonding pairs and two lone pairs. What is the molecular geometry?

Accepted Answer

T-shaped

Question 9

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

Accepted Answer

Electron geometry considers all electron groups, while molecular geometry considers only the arrangement of atoms.

Question 10

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

Accepted Answer

CO$$_2$$

Question 11

A molecule contains three identical polar bonds in a trigonal planar geometry. Is the molecule polar?

Accepted Answer

No, because the bond dipoles cancel due to symmetry.

Question 12

Which of the following statements is always true according to VSEPR theory?

Accepted Answer

The shape of a molecule is determined by repulsions among all electron groups on the central atom.

Question 13

What is the hybridization of the central atom in CO$$_2$$?

Accepted Answer

$$sp$$

Question 14

How many $$sp^3$$ hybrid orbitals are formed from the hybridization of one s and three p orbitals?

Accepted Answer

4

Question 15

According to valence bond theory, why is a double bond not simply twice as strong as a single bond?

Accepted Answer

A double bond consists of one $$\sigma$$ bond and one $$\pi$$ bond, and $$\pi$$ bonds are weaker than $$\sigma$$ bonds.

Question 16

What is the bond order for a diatomic molecule with 6 electrons in bonding molecular orbitals and 3 electrons in antibonding molecular orbitals?

Accepted Answer

$$\frac{6-3}{2} = 1.5$$

Question 17

Which of the following best describes a chemical bond according to molecular orbital (MO) theory?

Accepted Answer

Atoms bond when electrons can lower their energy by occupying molecular orbitals that belong to the whole molecule.

Question 18

Which of the following molecules is predicted to be paramagnetic based on molecular orbital theory?

Accepted Answer

O$$_2$$

Question 19

Which hybridization scheme is associated with an octahedral electron geometry?

Accepted Answer

$$sp^3d^2$

Question 20

Which of the following is a real-world consequence of molecular polarity?

Accepted Answer

Polar molecules dissolve well in water, affecting biological processes and drug delivery.

Molecular Shapes, VSEPR Theory, and Molecular Polarity: Study Notes

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