Question 1

Which statement best describes an electron orbital according to quantum theory?

Accepted Answer

An electron orbital is a region of space around the nucleus where there is a high probability of finding an electron.

Question 2

What is the shape of a 2p atomic orbital?

Accepted Answer

Dumbbell-shaped

Question 3

Which of the following best explains why $	ext{CH}_4$ (methane) has a tetrahedral geometry?

Accepted Answer

The carbon atom mixes its s and p orbitals to form four equivalent sp$^3$ hybrid orbitals.

Question 4

If four atomic orbitals are used to make molecular orbitals, how many molecular orbitals are produced?

Accepted Answer

Four

Question 5

What kind of molecular orbital will be generated when a 1s and a 2p$_x$ atomic orbital are combined with opposite phases?

Accepted Answer

Antibonding

Question 6

Which of the following is true about $	ext{sp}^2$ hybridization?

Accepted Answer

It involves mixing one s orbital and two p orbitals.

Question 7

Why can $	ext{pi}$ bonds not rotate freely around the bond axis?

Accepted Answer

Rotation would change the phase and orientation of the overlapping p orbitals, breaking the bond.

Question 8

Which of the following is a consequence of mixing atomic orbitals within an atom?

Accepted Answer

It creates new hybrid orbitals with ideal geometry, stabilizing the molecule.

Question 9

What is the bond angle in a molecule with $	ext{sp}^3$ hybridization?

Accepted Answer

$109.5^	ext{o}$

Question 10

Which molecular orbital is formed when two atomic orbitals combine in-phase?

Accepted Answer

Bonding molecular orbital

Question 11

In molecular orbital theory, what does the region of overlap with cylindrical symmetry correspond to?

Accepted Answer

$\sigma$ orbital

Question 12

Which of the following atoms can participate in linear ($sp$) hybridization?

Accepted Answer

Carbon, nitrogen, oxygen, and fluorine

Question 13

What is the main difference between a bonding and an antibonding molecular orbital?

Accepted Answer

Bonding orbitals have constructive overlap, while antibonding orbitals have destructive overlap.

Question 14

Which hybridization is present in the central carbon of ethyne ($	ext{C}_2	ext{H}_2$)?

Accepted Answer

$sp$

Question 15

What is the effect of hybrid orbitals on chemical properties?

Accepted Answer

They determine the geometry and bond angles of molecules, affecting reactivity and stability.

Question 16

Which of the following is true about the phase of a wavefunction in atomic orbitals?

Accepted Answer

Shading represents the sign (phase) of the function, not the charge.

Question 17

Which type of bond allows free rotation around the bond axis?

Accepted Answer

$\sigma$ bond

Question 18

What is a node in the context of atomic orbitals?

Accepted Answer

A region of zero electron density

Question 19

Which of the following best describes the process of hybridization?

Accepted Answer

Mixing atomic orbitals within an atom to form new orbitals with specific geometries

Question 20

In the molecule $	ext{C}_2	ext{H}_4$ (ethene), what is the hybridization of each carbon atom?

Accepted Answer

$sp^2$

Lecture Notes #2

Study Guide - Practice Questions