Describe the orbitals used in bonding and the bond angles in the following compounds:
a. CH₃O^-

Verified step by step guidance

1. Step 1: Identify the central atom in the compound CH₃O^-. The central atom is oxygen (O) in this case.
2. Step 2: Determine the hybridization of the central atom. Oxygen in CH₃O^- is sp³ hybridized because it forms three sigma bonds (one with carbon and two with hydrogen) and has one lone pair.
3. Step 3: Describe the orbitals involved in bonding. The oxygen atom uses its sp³ hybrid orbitals to form sigma bonds with the carbon atom and the hydrogen atoms. The carbon atom in CH₃ is also sp³ hybridized, using its sp³ orbitals to form sigma bonds with the oxygen and hydrogen atoms.
4. Step 4: Determine the bond angles. In an sp³ hybridized atom, the ideal bond angle is approximately 109.5°. However, due to the presence of a lone pair on oxygen, the bond angle may be slightly less than 109.5°.
5. Step 5: Consider the effect of the negative charge. The negative charge on the oxygen atom indicates an extra electron, which is accommodated in one of the sp³ hybrid orbitals, contributing to the overall geometry and bond angles.

Key Concepts

Hybridization

Hybridization is the process by which atomic orbitals mix to form new hybrid orbitals that are suitable for the pairing of electrons to form chemical bonds. In the case of CH3O-, the central atom (carbon) undergoes sp3 hybridization, resulting in four equivalent hybrid orbitals that can form sigma bonds with hydrogen and oxygen.

Bond Angles

Bond angles are the angles formed between adjacent bonds in a molecule, which are influenced by the hybridization of the central atom and the repulsion between electron pairs. In CH3O-, the bond angles around the carbon atom are approximately 109.5 degrees, characteristic of sp3 hybridization, while the bond angle between the carbon and oxygen may be slightly less due to lone pair repulsion.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms in a molecule, which is determined by the number of bonding pairs and lone pairs of electrons around the central atom. For CH3O-, the geometry is tetrahedral around the carbon atom, with the presence of a lone pair on the oxygen affecting the overall shape and bond angles.