Final answer:
The bond angle associated with a trigonal planar distribution of electron density is 120°, exemplified in molecules like BF3 where atoms are arranged in an equilateral triangle to minimize electron repulsion.
Step-by-step explanation:
The bond angle most closely associated with a trigonal planar distribution of electron density is 120°. In a molecule where the electron-pair geometry is trigonal planar, the molecular structure is also trigonal planar. An example of such a structure is BF3 where the three electron groups around the central atom spread out in the form of an equilateral triangle to minimize repulsion, resulting in bond angles of 120°. This arrangement of atoms and electron pairs ensures that they are as far apart as possible, creating the trigonal planar shape.