Question 1

Which statement best describes the difference between sigma ($\sigma$) and pi ($\pi$) bonds?

Accepted Answer

Sigma bonds result from head-to-head overlap of orbitals with cylindrical symmetry about the internuclear axis, while pi bonds result from side-to-side overlap with electron density above and below the axis.

Question 2

What is the hybridization of the central atom in $\mathrm{SF_6}$?

Accepted Answer

$sp^3d^2$

Question 3

In the molecule acetylene ($\mathrm{C_2H_2}$), what is the hybridization of each carbon atom?

Accepted Answer

$sp$

Question 4

Which of the following molecules or ions exhibits delocalized $\pi$ bonding?

Accepted Answer

$\mathrm{SO_3^{2-}}$

Question 5

How many $\sigma$ and $\pi$ bonds are present in the formaldehyde ($\mathrm{H_2CO}$) molecule?

Accepted Answer

3 $\sigma$ bonds and 1 $\pi$ bond

Question 6

Which hybridization corresponds to a trigonal bipyramidal electron-domain geometry?

Accepted Answer

$sp^3d$

Question 7

What is the bond angle expected around the central atom in $\mathrm{NH_4^+}$?

Accepted Answer

$109.5^\circ$

Question 8

In benzene ($\mathrm{C_6H_6}$), the $\pi$ electrons are:

Accepted Answer

Delocalized over all six carbon atoms

Question 9

Which of the following best explains why beryllium in $\mathrm{BeF_2}$ can form two bonds despite having filled $2s$ orbitals?

Accepted Answer

Beryllium promotes an electron and hybridizes its $2s$ and $2p$ orbitals to form two $sp$ hybrid orbitals.

Question 10

In the nitrate ion ($\mathrm{NO_3^-}$), what is the nature of the $\pi$ bonds?

Accepted Answer

The $\pi$ bonds are delocalized over all three oxygen atoms.

Question 11

Which hybridization is associated with a molecule that has a tetrahedral geometry?

Accepted Answer

$sp^3$

Question 12

How many $\pi$ bonds are present in the molecule acetonitrile ($\mathrm{CH_3CN}$)?

Accepted Answer

2

Question 13

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

Accepted Answer

$\mathrm{NH_4^+}$

Question 14

What is the hybridization of the central atom in $\mathrm{SO_3^{2-}}$?

Accepted Answer

$sp^3$

Question 15

Which statement about multiple bonds is correct?

Accepted Answer

A triple bond consists of one $\sigma$ bond and two $\pi$ bonds.

Question 16

In $\mathrm{SF_4}$, what is the hybridization of the central sulfur atom?

Accepted Answer

$sp^3d$

Question 17

Which of the following best describes the electron density in a $\pi$ bond?

Accepted Answer

It is distributed above and below the internuclear axis.

Question 18

Which molecule has a central atom with $sp^2$ hybridization?

Accepted Answer

$\mathrm{BF_3}$

Question 19

What is the total number of $\sigma$ and $\pi$ bonds in the acetonitrile ($\mathrm{CH_3CN}$) molecule?

Accepted Answer

5 $\sigma$ and 2 $\pi$ bonds

Valence Bond Theory, Hybridization, and Bond Types (Chapter 7 Study Notes)

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