Question 1

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electron pairs between atoms.

Question 2

Which statement about sigma ($$\sigma) $$and pi ($$\pi) $$bonds is correct?

Accepted Answer

A $$\sigma$$ bond is stronger than a $$\pi$$ bond and allows for free rotation.

Question 3

What is the bond order of the oxygen molecule ($$\mathrm{O_2$}) $$according to molecular orbital theory?

Accepted Answer

$$2$$

Question 4

Which of the following statements about hybrid orbitals is TRUE?

Accepted Answer

Hybrid orbitals are used to explain the shapes of molecules predicted by VSEPR theory.

Question 5

A molecule of ethene ($$\mathrm{C_2H_4}) $$contains which types of bonds between the two carbon atoms?

Accepted Answer

One $$\sigma$$ bond and one $$\pi$$ bond

Question 6

Which of the following best explains why rotation around a double bond is restricted?

Accepted Answer

Double bonds contain a $$\pi$$ bond, which prevents free rotation due to the side-to-side overlap of p orbitals.

Question 7

According to VSEPR theory, what is the expected hybridization of the central atom in methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

$$sp^3$$

Question 8

Which of the following molecules contains only $$\sigma$$ bonds?

Accepted Answer

$$\mathrm{H_2O}$$

Question 9

If a molecule has a bond order of zero, what does this indicate about the molecule?

Accepted Answer

The molecule does not exist under normal conditions.

Question 10

Which of the following best describes the process of orbital hybridization?

Accepted Answer

The mixing of atomic orbitals on the same atom to form new orbitals for bonding.

Question 11

A molecule of carbon dioxide ($$\mathrm{CO_2$}) $$has which hybridization on the central carbon atom?

Accepted Answer

$$sp$$

Question 12

Which of the following is a correct statement about the bonding in $$\mathrm{N_2$}$$?

Accepted Answer

$$\mathrm{N_2$}$$ has a triple bond consisting of one $$\sigma$$ and two $$\pi$$ bonds.

Question 13

Which of the following best explains why $$\mathrm{O_2$} is $$paramagnetic?

Accepted Answer

$$\mathrm{O_2$}$$ has unpaired electrons in its molecular orbitals.

Question 14

Which of the following molecules would you expect to have $$sp^2$$ hybridization on the central atom?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 15

Which of the following statements about molecular orbitals is correct?

Accepted Answer

Bonding molecular orbitals are lower in energy than the atomic orbitals from which they are formed.

Question 16

Which of the following best describes the difference between a $$\sigma$$ bond and a $$\pi$$ bond?

Accepted Answer

$$\sigma$$ bonds result from end-to-end overlap, while $$\pi$$ bonds result from side-to-side overlap of p orbitals.

Question 17

A molecule has a central atom with three bonding pairs and one lone pair. According to VSEPR theory, what is the expected hybridization of the central atom?

Accepted Answer

$$sp^3$$

Question 18

Which of the following is a real-world example of the importance of bond order?

Accepted Answer

The strength and length of the bond in $$\mathrm{O_2$}$$ affects its role in biological respiration.

Question 19

Which of the following molecules contains both $$\sigma$$ and $$\pi$$ bonds?

Accepted Answer

$$\mathrm{C_2H_2} ($$acetylene)

Question 20

Which of the following statements about free rotation in chemical bonds is correct?

Accepted Answer

Free rotation is possible around $$\sigma$$ bonds but not around $$\pi$$ bonds.

Hybridization and Molecular Orbital Theory: Covalent Bonding and Orbital Interactions

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