Question

Consider the following molecules or ions: ClO2+ , AsF6 - , IOF3,  and SOF2. Answer the following questions based on the Lewis structures and VSEPR theory prediction of their molecular shapes.

(a) Which one has only bond angles of 109.5°?

(b) Which one has only bond angles of 120°?

(c) Which one has bond angles of 90 and 180°?

(d) Which one has bond angles of 90, 120, and 180°?

Answer 1

The hybridisations of the given molecules are as follows:

Molecule or Ion	Hybridisation	Geometry
ClO2+	sp2	Trigonal Planar
AsF6-	sp3d2	Octahedral
IOF3	sp3d	Pyramidal
SOF2	sp3	Tetrahedral

(a).SOF₂ has only bond angles of 109.5°.This is because, in tetrahedral all the bond angles are 109.5°.

(b).ClO₂⁺ has bond angles of 120°.This is because it has trigonal planar geometry. So, all the atoms are in the same plane around the central atom.

(c). AsF₆^- has bond angles of 90° and 180°.This is because it has octahedral geometry which means four molecules in the same plane are making 90° with the central atom and 2 atoms above and below the plane making 180° with the central atom.

(d). IOF₃ has angles 90, 120 and 180°. This follows from the trigonal geometry of the molecule. It has three atoms in the plane making 120° with the central atom and bonds above and below the plane making 180° with the central atom.It also has 90° angle between planar molecules and axial molecules.