Q: Which equation is used to calculate the bond order in molecular orbital theory?

$$\text{Bond order} = \frac{1}{2}(\text{number of electrons in bonding MOs} - \text{number of electrons in antibonding MOs})$$

Question 1

Which of the following statements best describes the difference between valence bond (VB) theory and molecular orbital (MO) theory?

Accepted Answer

VB theory describes bonding as the overlap of atomic orbitals localized on individual atoms, while MO theory describes bonding as the combination of atomic orbitals to form molecular orbitals delocalized over the entire molecule.

Question 2

What is the hybridization of the central atom in SF6, and what is the resulting molecular geometry?

Accepted Answer

sp3d2 hybridization; octahedral geometry

Question 3

Which of the following molecules is predicted to be paramagnetic based on molecular orbital theory?

Accepted Answer

O2

Question 4

How many $$	ext{sp}^2$$ hybrid orbitals are formed when one s and two p orbitals are hybridized?

Accepted Answer

$$3$$

Question 5

Which of the following best explains why the bond order of He$$_2 is $$zero?

Accepted Answer

The number of electrons in bonding and antibonding molecular orbitals is equal, so $$	ext{Bond order} = \frac{1}{2}(2-2) = 0.$$

Question 6

In the molecule C$$_2H$_4 ($$ethylene), what type of bonds exist between the two carbon atoms?

Accepted Answer

One $$\sigma$$ bond and one $$\pi$$ bond

Question 7

Which hybridization is associated with a linear molecular geometry and a bond angle of $$180^\circ$$?

Accepted Answer

sp

Question 8

What is the bond order of the H$$_2^-$$ ion according to molecular orbital theory?

Accepted Answer

$$\frac{1}{2}$$

Question 9

Which of the following statements about $$\pi$$ bonds is correct?

Accepted Answer

$$\pi$$ bonds are formed by sideways overlap of unhybridized p orbitals.

Question 10

A molecule has five charge clouds around its central atom. What is the expected hybridization and geometry?

Accepted Answer

sp3d hybridization; trigonal bipyramidal geometry

Question 11

Which of the following best describes the effect of formal charge on the orbital-filling diagram of an atom?

Accepted Answer

A negative formal charge adds one valence electron to the atom, while a positive formal charge removes one.

Question 12

Which of the following molecules contains a central atom with sp$$^3d$^2$$ hybridization?

Accepted Answer

SF$$_6$$

Question 13

Which of the following is a consequence of the directional character of bonds formed by hybrid orbitals (other than s orbitals)?

Accepted Answer

Molecules adopt specific shapes such as tetrahedral, trigonal planar, or linear.

Question 14

Which of the following best explains why O$$_2 is $$paramagnetic?

Accepted Answer

O$$_2$$ has two unpaired electrons in its $$\pi^*$$ molecular orbitals.

Question 15

Which equation is used to calculate the bond order in molecular orbital theory?

Accepted Answer

$$	ext{Bond order} = \frac{1}{2}(	ext{number of electrons in bonding MOs} - 	ext{number of electrons in antibonding MOs})$$

Question 16

Which of the following molecules has a central atom with sp$$^2$$ hybridization and a trigonal planar geometry?

Accepted Answer

BF$$_3$$

Question 17

In the molecule C$$_2H$_2 ($$acetylene), how many $$\pi$$ bonds are present between the two carbon atoms?

Accepted Answer

Two

Question 18

Which of the following is true about resonance according to molecular orbital theory?

Accepted Answer

Resonance is explained by delocalized electrons in molecular orbitals that extend over the entire molecule.

Question 19

Which of the following best describes the geometry and hybridization of the central atom in PCl$$_5$$?

Accepted Answer

Trigonal bipyramidal geometry; sp$$^3d $$hybridization

Valence Bond Theory, Hybridization, and Molecular Orbital Theory

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