Question 1

Which hybridization scheme best explains the geometry and bond angles observed in methane (CH$$_4$$)?

Accepted Answer

$$sp^3$$ hybridization; bond angles of 109.5^\circ$

Question 2

Which of the following statements about the electron configuration of carbon in methane is correct?

Accepted Answer

Carbon uses one $$2s$$ and three $$2p$$ orbitals to form four $$sp^3$$ hybrid orbitals.

Question 3

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($$\ell)$$

Question 4

What is the formal charge on the central carbon atom in the Lewis structure of methane (CH$$_4$$)?

Accepted Answer

0

Question 5

Which of the following molecules has a net dipole moment of zero?

Accepted Answer

Carbon dioxide ($$CO_2)$$

Question 6

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

Accepted Answer

$$\sigma$$ bonds are stronger and formed by end-to-end overlap; $$\pi$$ bonds are weaker and formed by sideways overlap.

Question 7

Which of the following is a correct statement about resonance structures?

Accepted Answer

Resonance structures differ only in the placement of $$\pi$$ electrons and lone pairs.

Question 8

Which of the following atoms can have an expanded octet in a stable molecule?

Accepted Answer

Sulfur (S)

Question 9

What is the bond angle in a molecule with $$sp^2$$ hybridization around the central atom?

Accepted Answer

$$120^\circ$$

Question 10

Which of the following best explains why the four C–H bonds in methane are identical?

Accepted Answer

The carbon atom forms four $$sp^3$$ hybrid orbitals that are equivalent in energy and orientation.

Question 11

Which of the following is the correct electron configuration for the ground state of a neutral carbon atom?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^2$$

Question 12

Which of the following best describes the effect of resonance on the stability of a molecule?

Accepted Answer

Resonance lowers the energy and increases the stability of a molecule.

Question 13

Which of the following is a valid Lewis structure for the carbonate ion ($$CO_3$$^{2-}$$)?

Accepted Answer

A structure with one double bond and two single bonds, with negative charges on two oxygen atoms.

Question 14

Which of the following best describes the difference between localized and delocalized electrons in resonance structures?

Accepted Answer

Localized electrons are confined to a single atom or bond; delocalized electrons are spread over several atoms.

Question 15

Which of the following best explains why the bond angle in water ($$H_2O) is $$less than the ideal tetrahedral angle?

Accepted Answer

Lone pairs on oxygen repel the bonding pairs more strongly, reducing the bond angle.

Question 16

Which of the following is the correct order of bond strength for C–H bonds in different hybridizations?

Accepted Answer

$$sp^3$$ \u003c $$sp^2$$ \u003c sp$$

Question 17

Which of the following is a correct application of Hund's rule in electron configuration?

Accepted Answer

Electrons occupy each degenerate orbital singly with parallel spins before pairing.

Question 18

Which of the following best describes the inductive effect in organic molecules?

Accepted Answer

The shifting of electrons in a bond in response to the electronegativity of nearby atoms.

Question 19

Which of the following is true about the Pauli exclusion principle?

Accepted Answer

No two electrons in an atom can have the same four quantum numbers.

Chapter 1: Electronic Structure and Bonding in Organic Molecules

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