Molecular Geometry Practice Problems

There are four collinear atoms in hex-3-yne (CH₃CH₂CCCH₂CH₃). Draw its three-dimensional structure and circle all the atoms that are in a straight line with the triple bond.

Show the structure of cis-Cl-CH=C(Cl)-CH₂CH₃ with complete geometry around the double bond. Now, by drawing the trans isomer compare the number of coplanar atoms in both.

In most of the amines, the nitrogen has an sp³ hybridization with a pyramidal geometry having bond angles close to 109°. In contrast, the nitrogen atom in methanamide has sp² hybridization and trigonal planar geometry with bond angles of 120°, approximately. Explain this unusual behavior.

Find out the hybridization and bond angles (approximately) of the central atoms in the following molecules. Also, draw their three-dimensional structures including lone pairs of electrons (if any).

a. HCOOH
b. (CH₃CH₂)₃N
c. [CH₃CH₂NH₃]⁺

Determine the hybridization of the central atoms in the given compound to predict their bond angles and geometry.

• CH₂=N-CH₃

Give the hybridization, bond angles, and geometry of central atoms in the following compound.

• Prop-1-ene, CH₂=CHCH₃

Provide the hybridization of each carbon atom and approximate the bond angles of the given molecule.

CH₃CH₂CH═CH—CH═CHCH₃

Predict the molecular geometry and the Lewis structure of HCO ₂^–.

Estimate the bond angles for the bonds mentioned below.

a. the H—C—N bond in HC≡N.

b. the C—C—N bond in CH₃CH₂NHCH₃.

Indicate the hybridization and predict the approximate bond angles for each of the carbons in acetylene (HC≡CH).

Do the indicated sp³ carbons lie in the same plane as the sp² carbons in the following molecules?

Identify which of the given species have 109.5° bond angles and which have 120° bond angles around their central atom.

a. AlCl₃

b. CCl₄

c. NH₄⁺

d. BH₃

Briefly explain why the given structure is unstable.

Estimate the bond angles for the C—N—C bonds in a tertiary amine.

Estimate the bond angles in the following.

a. tert-butyl radical

b. tert-butyl cation

c. tert-butyl anion

What orbitals are used in the bonding in AlH₃? Also, describe the bond angles in it.

Keeping the resonance in mind, suggest the hybridization and geometry of the central atoms (only carbon and nitrogen) in the given species.

Encircle the atoms that will most likely lie on the same plane.