Question 1

All of the following statements concerning molecular orbital (MO)theory are correct EXCEPT
A) the Pauli exclusion principle is obeyed.
B) Hund's rule is obeyed.
C) electrons are assigned to orbitals of successively higher energy.
D) a bonding molecular orbital is lower in energy than its parent atomic orbitals.
E) the combination of two atomic orbitals creates only one molecular orbital.

Accepted Answer

The combination of two atomic orbitals creates two molecular orbitals, one lower in energy (the bonding MO) and one higher in energy (the anti-bonding MO).

Question 2

Ammonia reacts with oxygen and water to produce nitric acid.What change in hybridization of the nitrogen atom occurs in this reaction? A) sp³ to sp² B) sp³ to sp C) sp² to sp³ D) sp² to sp E) no change

Accepted Answer

The answer of Ammonia reacts with oxygen and water to...

Question 3

Which of the following concerning $\sigma$ and $\pi$ bonds is/are correct?
1)Sigma bonds may only be formed from unhybridized orbitals.
2)Pi bonds are formed from unhybridized p orbitals.
3)A pi bond has an electron distribution above and below the bond axis.
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 2 and 3

Accepted Answer

1) Sigma bonds can be formed from hybridized or unhybridized orbitals.
2) Pi bonds are formed from unhybridized p orbitals.
3) A pi bond has an electron distribution above and below the bond axis, creating a double bond.

Question 4

Upon combustion,ethene (C₂H₄)is converted to carbon dioxide and water.What change in the hybridization of carbon occurs in this reaction? A) sp to sp² B) sp² to sp³ C) sp³ to sp D) sp² to sp E) sp³ to sp²

Accepted Answer

In ethene, the two carbon atoms are sp2 hybridized, with one unhybridized p orbital that forms the pi bond between them. Upon combustion, one carbon atom bonds with two oxygen atoms to form carbon dioxide, while the other carbon atom bonds with two hydrogen atoms and an oxygen atom to form water. This results in the loss of the pi bond, and the remaining carbon atom becomes sp hybridized with a linear geometry, allowing it to form the double bond with one of the oxygen atoms in carbon dioxide. Therefore, the hybridization of carbon changes from sp2 to sp. Choice D correctly describes this change, as it states that the carbon changes from sp2 to sp.

Question 5

For which of the following compounds is it possible for cis and trans isomers to exist? 
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 1,2,and 3

Accepted Answer

The answer of For which of the following compounds is...

Question 6

Which of the underlined atoms (C₁,C₂,N,and O)are sp hybridized? A) C₁ and C₂ B) C₁,C₂,N,and O C) N and O D) C₁,C₂,and N E) none

Accepted Answer

The answer of Which of the underlined atoms (C₁,C₂,N,and O)are...

Question 7

What is the hybridization of an atom that has 1 $\sigma$ bond,0 $\pi$ bonds,and 3 lone pairs? A) sp B) sp² C) sp³ D) sp⁴ E) none

Accepted Answer

The atom has 3 lone pairs and forms 1 sigma bond and 0 pi bonds, indicating sp3 hybridization. However, since there is a lone pair in the p orbital, there is some amount of unhybridized p character, hence the hybridization is sp3d, which is represented as sp³.

Question 8

Dichloromethane,CH₂Cl₂,is a common organic solvent.Which of the following statements concerning dichloromethane is/are CORRECT? 1)CH₂Cl₂ has two isomers.For one isomer of CH₂Cl₂,the chlorine atoms are adjacent to each other and the molecule is polar. 2)CH₂Cl₂ has two isomers.For one isomer of CH₂Cl₂,the chlorine atoms are on opposites sides of the carbon atom and the molecule is nonpolar. 3)The hybridization of the central carbon atom is sp³. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1,2,and 3

Accepted Answer

Dichloromethane (CH₂Cl₂) does not have isomers because it is a simple molecule with two identical chlorine atoms bonded to a single carbon atom. The hybridization of the central carbon atom in CH₂Cl₂ is sp³, as it forms four sigma bonds with two hydrogen atoms and two chlorine atoms.

Question 9

What is the hybridization of the nitrogen atom? A) sp B) sp² C) sp³ D) sp⁴ E) none

Accepted Answer

The nitrogen atom has two regions of electron density, one from the double bond to oxygen and the other from the lone pair of electrons on nitrogen. Therefore, it requires two hybrid orbitals to accommodate these electrons, which are sp hybrid orbitals. The remaining two unhybridized p orbitals on nitrogen are perpendicular to the plane of the sp hybrid orbitals and participate in pi-bonding with the oxygen atom, resulting in the sp² hybridization.

Question 10

Which of the following characteristics apply to NCl₃? 1)polar bonds 2)nonpolar molecule 3)triangular-planar molecular shape 4)sp² hybridized N atom A) 1 only B) 1 and 2 C) 3 and 4 D) 1,2,and 3 E) 1,2,3,and 4

Accepted Answer

NCl₃ has polar bonds due to the difference in electronegativity between nitrogen and chlorine, but it is not a nonpolar molecule, nor does it have a triangular-planar shape or sp² hybridization.

Question 11

Nitric acid,HNO₃,dissociates in water to form nitrate ions and hydronium ions.What change in hybridization of the nitrogen atom occurs in this dissociation? A) sp² to sp³ B) sp² to sp C) sp³ to sp D) sp to sp³ E) no change

Accepted Answer

The answer of Nitric acid,HNO₃,dissociates in water to form nitrate...

Question 12

Which of the following hybridized atoms is not possible? A) an sp hybridized nitrogen atom B) an sp² hybridized oxygen atom C) an sp³ hybridized boron atom D) an sp³ hybridized phosphorus atom E) an sp³ hybridized hydrogen atom

Accepted Answer

Hydrogen can only form one bond and does not have orbitals to hybridize, so it cannot be sp³ hybridized.

Question 13

What is the molecular geometry around a central atom that is sp² hybridized,has three sigma bonds,and one pi bond? A) trigonal-planar B) trigonal-pyramidal C) bent D) T-shaped E) tetrahedral

Accepted Answer

The hybridization of sp^2 indicates three hybrid orbitals, which, combined with the presence of three sigma bonds and one pi bond, suggests a trigonal-planar molecular geometry. This configuration allows for the arrangement of three bonded atoms and the pi bond in a planar structure around the central atom.

Question 14

Atomic orbitals combine most effectively to form molecular orbitals when
A) electrons in the orbitals have no spins.
B) electrons in the orbitals have the same spin.
C) the atoms have an equal number of valence electrons.
D) the atomic orbitals have similar energies.
E) only d-orbitals are used in bonding.

Accepted Answer

Atomic orbitals combine most effectively to form molecular orbitals when they have similar energies. This allows for better overlap and interaction between the orbitals, leading to stronger and more stable bonds.

Question 15

Which of the following concerning $\sigma$ and $\pi$ bonds is/are correct?
1)A sigma bond may be formed from the sideways overlap of two parallel p orbitals.
2)No more than two pi bonds are possible between adjacent carbon atoms.
3)The considerable energy required to rotate pi bonded atoms is the primary reason for geometrical isomerism in some pi bonded molecules.
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 2 and 3

Accepted Answer

A sigma bond is formed by the end-to-end overlap of orbitals, not sideways. Two pi bonds can exist between adjacent carbon atoms, as seen in triple bonds. Pi bonds restrict rotation, leading to geometrical isomerism.

Question 16

Which of the labeled carbon atoms (C₁-C₄)is/are sp hybridized? A) C₁ B) C₁ and C₂ C) C₃ D) C₂ and C₄ E) C₁ and C₃

Accepted Answer

The answer of Which of the labeled carbon atoms (C₁-C₄)is/are...

Question 17

When an atom in a molecule or ion is described as sp³ hybridized,its electron pair geometry is A) linear B) triangular planar C) triangular pyramidal D) bent E) tetrahedral

Accepted Answer

The sp³ hybridization corresponds to a tetrahedral electron pair geometry, with four hybrid orbitals arranged around the central atom.

Question 18

A molecular orbital that decreases the electron density between two nuclei is said to be ____.
A)hybridized
B)bonding
B)antibonding
D)pi-bonding
E)nonpolar

Accepted Answer

The answer of A molecular orbital that decreases the electron...

Question 19

What is the molecular geometry around an atom that has 2 $\sigma$ bonds,0 $\pi$ bonds,and 1 lone pair of electrons?
A) linear
B) trigonal planar
C) tetrahedral
D) bent
E) trigonal pyramidal

Accepted Answer

The answer of What is the molecular geometry around an...

Question 20

Diagram 9-1 The molecular orbital diagram below may be used for the following problem(s).For oxygen and fluorine,the $\sigma$_2p orbital should be lower in energy than the $\pi$_2p orbitals.However,the diagram will still yield correct bond order and magnetic behavior for these molecules. -Refer to Diagram 9-1.According to molecular orbital theory,which of the following species will have the $\underline{\text{ highest }}$ bond order? A) B₂⁺ B) H₂ C) F₂⁺ D) N₂⁺ E) O₂^2-

Accepted Answer

N₂⁺ has the highest bond order because it has the most bonding electrons and the fewest antibonding electrons.

Quiz 10: Bonding and Molecular Structure: Orbital Hybridization and Molecular Orbitals

All of the following statements concerning molecular orbital (MO) theory are correct EXCEPT

Ammonia reacts with oxygen and water to produce nitric acid.What change in hybridization of the nitrogen atom occurs in this reaction?

Which of the following concerning $\sigma$ and $\pi$ bonds is/are correct? 1) Sigma bonds may only be formed from unhybridized orbitals. 2) Pi bonds are formed from unhybridized p orbitals. 3) A pi bond has an electron distribution above and below the bond axis.

Upon combustion,ethene (C₂H₄) is converted to carbon dioxide and water.What change in the hybridization of carbon occurs in this reaction?

For which of the following compounds is it possible for cis and trans isomers to exist?

Which of the underlined atoms (C₁,C₂,N,and O) are sp hybridized?

What is the hybridization of an atom that has 1 $\sigma$ bond,0 $\pi$ bonds,and 3 lone pairs?

What is the hybridization of the nitrogen atom?

Which of the following characteristics apply to NCl₃? 1) polar bonds 2) nonpolar molecule 3) triangular-planar molecular shape 4) sp² hybridized N atom

Nitric acid,HNO₃,dissociates in water to form nitrate ions and hydronium ions.What change in hybridization of the nitrogen atom occurs in this dissociation?

Which of the following hybridized atoms is not possible?

What is the molecular geometry around a central atom that is sp² hybridized,has three sigma bonds,and one pi bond?

Atomic orbitals combine most effectively to form molecular orbitals when

Which of the labeled carbon atoms (C₁-C₄) is/are sp hybridized?

When an atom in a molecule or ion is described as sp³ hybridized,its electron pair geometry is

A molecular orbital that decreases the electron density between two nuclei is said to be ____. A)hybridized B)bonding B)antibonding D)pi-bonding E)nonpolar

What is the molecular geometry around an atom that has 2 $\sigma$ bonds,0 $\pi$ bonds,and 1 lone pair of electrons?

Quiz 10: Bonding and Molecular Structure: Orbital Hybridization and Molecular Orbitals

All of the following statements concerning molecular orbital (MO) theory are correct EXCEPT

Ammonia reacts with oxygen and water to produce nitric acid.What change in hybridization of the nitrogen atom occurs in this reaction?

Which of the following concerning σ\sigmaσ and π\piπ bonds is/are correct? 1) Sigma bonds may only be formed from unhybridized orbitals. 2) Pi bonds are formed from unhybridized p orbitals. 3) A pi bond has an electron distribution above and below the bond axis.

Upon combustion,ethene (C2H4) is converted to carbon dioxide and water.What change in the hybridization of carbon occurs in this reaction?

For which of the following compounds is it possible for cis and trans isomers to exist?

Which of the underlined atoms (C1,C2,N,and O) are sp hybridized?

What is the hybridization of an atom that has 1 σ\sigmaσ bond,0 π\piπ bonds,and 3 lone pairs?