Question 1

Which statement best explains why the bond angle in water ($\mathrm{H_2O}$) is $104.5^\circ$ rather than the expected $109.5^\circ$ for a tetrahedral arrangement?

Accepted Answer

The bond angle is reduced due to the presence of two lone pairs on oxygen, which compress the angle between the hydrogen atoms.

Question 2

According to the Valence Shell Electron-Pair Repulsion (VSEPR) theory, which of the following molecules has the largest bond angle?

Accepted Answer

$\mathrm{BeF_2}$

Question 3

Which hybridization is present in the central atom of $\mathrm{BF_3}$?

Accepted Answer

$sp^2$

Question 4

A molecule of $\mathrm{CO_2}$ is known to be linear and nonpolar. Which feature of its structure leads to the absence of a dipole moment?

Accepted Answer

The bond dipoles are equal and arranged symmetrically, cancelling each other out.

Question 5

Which of the following molecules is expected to have a dipole moment?

Accepted Answer

$\mathrm{SO_2}$

Question 6

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

Accepted Answer

$2$

Question 7

Which type of orbital overlap is responsible for the formation of a $\sigma$ (sigma) bond?

Accepted Answer

Head-to-head overlap of atomic orbitals

Question 8

In the molecule $\mathrm{SF_4}$, what is the electron geometry and the hybridization of the central atom?

Accepted Answer

Trigonal bipyramidal, $dsp^3$

Question 9

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

Accepted Answer

Bonding pairs are shared between two nuclei and are relatively confined, while lone pairs are centered around one nucleus and compress bond angles.

Question 10

Which molecule is paramagnetic according to its molecular orbital diagram?

Accepted Answer

$\mathrm{O_2}$

Question 11

What is the hybridization of the central atom in $\mathrm{XeF_4}$?

Accepted Answer

$d^2sp^3$

Question 12

Which of the following molecules has a trigonal planar geometry?

Accepted Answer

$\mathrm{BF_3}$

Question 13

If a molecule has four electron domains around the central atom, what is the expected hybridization?

Accepted Answer

$sp^3$

Question 14

Which of the following best describes the difference between bonding and antibonding molecular orbitals?

Accepted Answer

Bonding orbitals are formed by constructive combinations of atomic orbitals, while antibonding orbitals are formed by destructive combinations and have a nodal plane.

Question 15

Which molecule is expected to have the smallest bond angle among the following: $\mathrm{H_2O}$, $\mathrm{NH_3}$, $\mathrm{CH_4}$?

Accepted Answer

$\mathrm{H_2O}$

Question 16

What is the bond order of $\mathrm{He_2}$ according to molecular orbital theory?

Accepted Answer

$0$

Question 17

Which of the following molecules is expected to be diamagnetic?

Accepted Answer

$\mathrm{N_2}$

Question 18

In the molecule $\mathrm{PF_5}$, what is the geometry and hybridization of the central atom?

Accepted Answer

Trigonal bipyramidal, $dsp^3$

Question 19

Which of the following statements about the VSEPR model is correct?

Accepted Answer

It can predict the structure of molecules with hundreds of atoms.

Question 20

Which of the following molecules or ions has an octahedral electron geometry?

Accepted Answer

$\mathrm{SF_6}$

Molecular Structure and Orbitals: VSEPR, Hybridization, and Molecular Orbital Theory

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