What is the difference between trigonal pyramidal molecular shape vs. trigonal planar molecular shape? Why does the bond angle change between these molecular shapes when they both
include 3 attached atoms?

Explained below.

Explanation:

- The difference in shape is that in the form of 3D view, trigonal planar resembles a flat triangle, while trigonal pyramidal looks like a pyramid.

- For trigonal planar, the bond angle is 120°, whereas in trigonal pyramidal, the bond angle is 107°. This lesser in trigonal pyramidal due to the lone pair that subdues the bonding pairs that are hybridized whereas in trigonal planar, there is no lone pair.

your answer would be “dry”