Question

Which of the following ranks the molecules OF₂, BF₃, and CF₄ in order of their bond angles, from smallest to largest?

a) OF₂ < BF₃ < CF₄
b) CF₄ < OF₂ < BF₃
c) BF₃ < OF₂ < CF₄
d) BF₃ < CF₄ < OF₂

Answer 1

The ranking of the bond angles from smallest to largest for OF₂, BF₃, and CF₄ is OF₂ < BF₃ < CF₄, considering the electron pair geometry and molecular shape influenced by the presence or absence of lone pairs on the central atom.

Step-by-step explanation:

The question is asking to rank the molecules OF₂, BF₃, and CF₄ in order of their bond angles, from smallest to largest. When comparing the bond angles in these molecules, we must consider the electron pair geometry and molecular geometry. The bond angle will generally decrease with the increase in the number of lone pairs around a central atom due to lone pair-bond pair repulsion being greater than bond pair-bond pair repulsion.

For OF₂, the central atom O has two lone pairs and two bond pairs, leading to a bent shape from the tetrahedral electron pair geometry and smaller bond angles (<120°). In BF₃, the central atom B has no lone pairs and three bond pairs, creating a trigonal planar shape with 120° bond angles. The molecule CF₄ has a central carbon atom with no lone pairs and four bond pairs, resulting in a tetrahedral shape with bond angles of 109.5°.

The correct ranking of the bond angles from smallest to largest is OF₂ < BF₃ < CF₄ (Option a).