Do all of the following molecules contain at least one bond angle at 120 degrees: SeS3, SeS2, PCl5, TeCl4, ICI3, and XeCl2?

No, because two of the molecules have no bond angles at 120 °.

To answer this question, you must draw the Lewis structures of the compounds and determine their VSEPR shapes.

##"SeS"_3##

The Lewis structure of ##"SeS"_3## is

(from www.homeworklib.com)

This is an ##"AX"_3## molecule, and its geometry is trigonal planar.

All bond angles in a trigonal planar molecule are approximately 120 °.

##"SeS"_2##

The Lewis structure of ##"SeS"_2## is

##:stackrel(". .")("S")=stackrel(". .")("Se")=stackrel(". .")("S"):##

This is an ##"AX"_2"E"## molecule.

Its electron geometry is trigonal planar.

The bond angle in an ##"AX"_2"E"## molecule is approximately 120 °.

##"PCl"_5##

The Lewis structure of ##"PCl"_5## is

This is an ##"AX"_5## molecule, and its geometry is trigonal pyramidal.

The equatorial bond angles in a trigonal bipyramidal molecule are all 120 °.

##"TeCl"_4##

The Lewis structure of ##"TeCl"_4## is

This is an ##"AX"_4"E"## molecule.

Its electron geometry is trigonal pyramidal.

The equatorial bond angle between the equatorial ##"Te-Cl"## bonds is approximately 120 °.

##"ICl"_3##

The Lewis structure of ##"ICl"_3## is

This is an ##"AX"_3"E"_2## molecule.

Its electron geometry is trigonal pyramidal, and its molecular geometry is T-shaped.

The ##"I-Cl"## bond angles in a T-shaped molecule are both approximately 90 °.

##"XeCl"_2##

The Lewis structure of ##"XeCl"_2## is

This is an ##"AX"_2"E"_3## molecule.

Its electron geometry is trigonal pyramidal, with the lone pairs in the equatorial positions.

The molecule is linear, with a ##"Cl-Xe-Cl"## bond angle of 180 °.