For each of the following molecules, indicate the hybridization of each carbon and give the approximate values of all the bond angles:
d. CH₂═CH—CH═CH₂

Verified step by step guidance

1. Step 1: Identify the structure of the molecule CH₂═CH—CH═CH₂. This molecule consists of four carbon atoms connected in a conjugated system with alternating double and single bonds. The structure is linear for the double-bonded carbons and planar for the entire molecule due to conjugation.
2. Step 2: Determine the hybridization of each carbon atom. For a carbon atom involved in a double bond (C═C), it is sp² hybridized because it forms three sigma bonds (one sigma bond with the other carbon and two sigma bonds with hydrogens or adjacent carbons) and one unhybridized p orbital forms the π bond.
3. Step 3: Assign the hybridization to each carbon atom in the molecule. The first and last carbons (CH₂ groups) are sp² hybridized because they are part of a double bond. The middle two carbons (CH groups) are also sp² hybridized for the same reason.
4. Step 4: Determine the bond angles around each carbon atom. For sp² hybridized carbons, the bond angles are approximately 120° because the electron domains are arranged in a trigonal planar geometry to minimize electron repulsion.
5. Step 5: Summarize the results. All four carbon atoms in CH₂═CH—CH═CH₂ are sp² hybridized, and the bond angles around each carbon are approximately 120°. The molecule is planar due to the conjugated π system.

Key Concepts

Hybridization

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can accommodate the bonding requirements of a molecule. In organic chemistry, carbon typically undergoes sp3, sp2, or sp hybridization depending on its bonding. For example, sp2 hybridization involves one s and two p orbitals mixing to form three equivalent sp2 hybrid orbitals, which are arranged in a trigonal planar geometry.

Bond Angles

Bond angles are the angles formed between adjacent bonds in a molecule, which are influenced by the hybridization of the atoms involved. For sp3 hybridized carbons, the bond angle is approximately 109.5 degrees, while for sp2 hybridized carbons, the bond angle is about 120 degrees. Understanding bond angles helps predict the molecular geometry and reactivity of organic compounds.

Alkenes and Their Structure

Alkenes are hydrocarbons that contain at least one carbon-carbon double bond, which affects their hybridization and geometry. In the given molecule CH2═CH—CH═CH2, the carbon atoms involved in double bonds are sp2 hybridized, leading to a planar structure around those carbons. This structural characteristic influences the bond angles and overall reactivity of the alkene.