Advanced Theory of Bonding

Explain how σ and π bonds are similar and how they are different.

Differences: σ bonds are stronger and result from end-to-end overlap and all single bonds are σ bonds; π bonds between the same two atoms are weaker because they result from side-by-side overlap, and multiple bonds contain one or more π bonds (in addition to a σ bond) Similarities: Both types of bonds result from overlap of atomic orbitals on adjacent atoms.

For the carbonate ion, CO32- , which of the following is a correct description of its bonding?

In the structure, the carbon is sp2 hybridized, and each of the three sp2 orbitals overlaps with an oxygen orbital to create a σ bond. The unhybridized p orbital on the carbon atom overlaps with a p orbital on the oxygen atom to create a π bond.

Which of the following molecules are paramagnetic according to molecular orbital theory?

O2

Which statement best describe the structure of a carbonate anion CO32- ?

The electron geometry of carbon in a carbonate anion is trigonal planar with a sp2 hybridization and bond angles are 120°. There is a π-bond formed between a non-hybridized "C" p-orbital overlapping with an "O" p-orbital.

Based on valence bond theory, which statement best describes the electron geometry, bonding and hybridization of the central atom in carbon tetrachloride CCl4 ?

The electron geometry of carbon in carbon tetrachloride is tetrahedral with a sp3 hybridization. The C-Cl bond is of σ-character.

Based on valence bond theory, which statement best describes the electron geometry and hybridization of the central atom(s) in acetylene HCCH?

The electron geometry of the 2 carbons in acetylene is linear with a sp hybridization.

Based on valence bond theory, what is the hybridization of the central atom(s) in C2F4?

both carbons are sp2

Which of the following figure represents the formation of a σ* antibonding molecular orbital?

bowtie split in the middle

Draw the Lewis structure for CO, and predict the number of σ and π bonds it has.

it has one σ and two π

Draw the Lewis structure for CO2, and predict the number of σ and π bonds for it.

it has two σ and two π

Give the shape that describes the hybrid orbital set sp :

linear

Predict the molecular geometry of XeF2 molecule by VSEPR.

linear

For many years after they were discovered, it was believed that the noble gases could not form compounds. Now we know that belief to be incorrect. A mixture of xenon and fluorine gases, confined in a quartz bulb and placed on a windowsill, is found to slowly produce a white solid. Analysis of the compound indicates that it is XeF2. Predict the shape of the molecules of the compound, what hybridization is consistent with the shape you predicted?

linear, sp3d hybridization

Which element contains triple covalent bonds?

nitrogen

Give the shape that describes the hybrid orbital set sp3d2 :

octahedral

Identify the hybridization of the central atom in CS2

sp

What is the hybridization of the central atom in BeH2 ?

sp

Identify the hybridization of the atom C in H2CCH2 .

sp2

Methionine, CH3SCH2CH2CH(NH2)CO2H, is an amino acid found in proteins. Lewis structure of this compound is shown below. What is the hybridization type of the nitrogen?

sp3

Methionine, CH3SCH2CH2CH(NH2)CO2H, is an amino acid found in proteins. Lewis structure of this compound is shown below. What is the hybridization type of the sulfur?

sp3

What is the hybridization of the central atom in PO43- ?

sp3

What is the hybridization of the central atom in PCl5 ?

sp3d

What is the hybridization of the central atom in SF6 ?

sp3d2

What is the hybridization of the central atom in XeF4 ?

sp3d2

Give the shape that describes the hybrid orbital set sp3 :

tetrahedral

Give the shape that describes the hybrid orbital set sp3d :

trigonal bipyramidal

Give the shape that describes the hybrid orbital set sp2 :

trigonal planar

Predict the molecular geometry of SO3 molecule by VSEPR.

trigonal planar

Predict the geometry about the first carbon atom (on the left), determine the hybridization type of this carbon.

trigonal planar, sp2

How many σ and π bonds are present in the molecule HCN (H-C≡N) ?

two σ (H—C and C—N) and two π