The bond angles marked a, b, and c in the molecule below are about __________, __________, and __________, respectively.
A)90°, 90°, 90°
B)120°, 120°, 90°
C)120°, 120°, 109.5°
D)109.5°, 120°, 109.5°
E)109.5°, 90°, 120°

Question

The bond angles marked a, b, and c in the molecule below are about __________, __________, and __________, respectively. 
A)90°, 90°, 90° 
B)120°, 120°, 90° 
C)120°, 120°, 109.5° 
D)109.5°, 120°, 109.5° 
E)109.5°, 90°, 120°

Quizplus · Accepted Answer

The molecule shown is trigonal bipyramidal, which has bond angles of 90° (axial equatorial), 120° (equatorial-equatorial), and 109.5° (axial-equatorial). Bond angle "a" is between an axial bond and an equatorial bond, so it is 109.5°. Bond angle "b" is between two equatorial bonds, so it is 120°. Bond angle "c" is between two axial bonds, so it is also 109.5°. Therefore, the best choice is D, which has the correct bond angles for this type of molecule.

The Bond Angles Marked A, B, and C in the Molecule