Chapter 3 Orbital Interactions

How many sp3 hybridized carbons does mycomycin have? How many sp2 hybridized carbons does it have? How many sp hybridized carbons does it have?

1,7,5 and counting that was annoying

How many bonding and antibonding molecular orbitals are there in methane, CH4?

Each C-H bond has a bonding and antibonding molecular orbital, and there are four such bonds in methane.

Based on what you have learned about nodes and orbitals, how many nodal planes are there in a 4p orbital?

Each p orbital, regardless of its energy level, has one nodal plane between its two lobes.

HOMO of ammonia s N-H π* N-H π N-H σ* nonbonding MO p N-H σ

Electrons contained in the N-H σ orbital are lower-energy electrons than others that exist in the molecule.

What are the hybridization states for the C, N, and O atoms in the molecule CH2NOH?

The C and N atoms have electrons going in three directions and thus are sp2 hybridized. The O atom has electrons going in four directions and thus is sp3 hybridized.

acetonitrile Which hybrid orbitals make up the C-C σ bond? Which hybrid orbitals make up the C-N σ bond?

The CH3 carbon is sp3 hybridized and the nitrile carbon is sp hybridized. The nitrile carbon and nitrogen are sp hybridized.

Acetonitrile has the formula CH3CN. Match the correct hybridization and electron geometry for each nonhydrogen atom.

The carbon of the CH3 group is sp3 hybridized. The carbon of the nitrile requires sp hybridization. This leaves two p orbitals to form π bonds to the adjacent nitrogen atom, which must also be sp hybridized.

The structure below is called the neocarzinostatin core. For these questions, just consider the carbon framework, which is why the hydrogens are omitted. How many σ bonds are in the carbon framework of this structure? How many π bonds are in the structure?

The first bond between any two atoms is a σ bond and there are 13 σ bonds in this molecule. Double bonds contains a σ bond and π bond, and a triple bond contains a σ bond and two π bonds. This molecule contains two double bonds and two triple bonds, and therefore it has 6 π orbitals. I hate counting

Consider a carbon atom that is sp hybridized. Indicate how many of each orbital exist on this carbon atom by sorting each orbital type. Consider the outer valence only.

s orbitals- 0 sp orbitals-2 p-orbitals-2 When an atom is sp hybridized, it has two sp hybrid orbitals and two unhybridized p orbitals.

What is the percentage of p character in the hybrid orbitals on the carbon atom in methane?

All carbons are sp3 hybridized; therefore, each hybrid orbital is 25% s and 75% p.

What is the shape of an sp3 hybrid orbital?

An sp3 orbital has two lobes, one much smaller than the other. Because of its relatively high percentage of p character, the lobes are more elongated than they are spherical.

The molecule below has 10 σ bonds. H2C=CH-C=o-ch3 How many of them involve sp3-s orbitals? How many involve sp3-sp2 orbitals? How many involve sp2-sp2 orbitals? How many involve sp2-s orbitals?

Based on the hybridizations of each nonhydrogen atom, there are three sp3-s bonds. Based on the hybridizations of each nonhydrogen atom, there is one sp3-sp2 bond. Based on the hybridizations of each nonhydrogen atom, there are three sp2-sp2 bonds. Based on the hybridizations of each nonhydrogen atom, there are three sp2-s bonds.

LUMO of ammonia s N-H π* N-H π N-H σ* nonbonding MO p N-H σ

Trigonal pyramidal ammonia has three fully occupied N-H σ bonding orbitals and three associated empty N-H σ* antibonding orbitals (the LUMO).

*Below* is the structure for the amino acid glycine. Which bond angles are closest to the actual values for the H-N-C and O-C-O bond angles? Consider all lone pairs of electrons as substituents when answering this question.

The nitrogen atom has four electron groups (one lone pair and three atoms), so it has tetrahedral electron geometry but trigonal pyramidal molecular geometry. As a result, it has a bond angle of 109.5º. The carbon atom has three electron groups (three bonds, but no lone pairs), so it has trigonal planar electron geometry and trigonal planar molecular geometry. As a result, it has a bond angle of 120º.

How many molecular orbitals are generated from the linear combination of two sp2 orbitals?

The number of atomic orbitals that are combined is equal to the number of molecular orbitals that are generated. Because we are combining two atomic orbitals, the result is two molecular orbitals.

Which of the following statements is the best explanation for the shapes of atomic orbitals? - The shape of an orbital encompasses all the possible locations of an electron around a nucleus. -None of the other statements correctly explains why orbitals have the shapes they do. -Orbital shapes have no physical meaning, but we draw different shapes to distinguish orbitals from each other. -Orbital shapes describe the path traveled by an electron as it moves around the nucleus. -The shape of an orbital describes a surface that encompasses about 90% of the probability of finding an electron around a nucleus.

The shape of an orbital describes a surface that encompasses about 90% of the probability of finding an electron around a nucleus. The shapes of orbitals are generated by creating surfaces that encompass most of the probability of finding an electron around a nucleus. Typically, we include 90% of that probability.

How many combinations are possible when two p orbitals are combined? (drop the linear in the question for it to make sense)

Two orbitals can be combined in phase (resulting in constructive interference) or out of phase (resulting in destructive interference) to produce two new orbitals.

Answer the questions about the alkene below. Select all of the atoms that are in the same plane. Does this alkene have a cis or trans configuration?

When two atoms are connected by a double bond, those atoms and any atoms to which they are directly bonded strongly prefer to lie in the same plane. Substituents on alkenes with a trans configuration are on opposite sides of the double bond.