Final answer:
In a molecule with trigonal planar geometry, there are typically three 120° bond angles around the central atom. This is common in carbonyl groups and molecules like BF3. The presence of lone pairs can alter bond angles from their ideal values due to repulsion effects.
Step-by-step explanation:
The question pertains to the number of 120° bond angles in a molecule. According to the information provided, the molecule in question is likely to have a trigonal planar geometry, which is characterized by atoms arranged around a central atom in the shape of a triangle with 120° angles between each bond. For example, in a carbonyl group (C=O), the geometry of the bonds around the central carbon is indeed trigonal planar with bond angles of 120°.
In molecules like BF3 or CO2, this type of geometry also occurs, with CO2 being linear but having double bonds that are symmetrically arranged, resulting in an effectively straight angle (180°). It's important to note that when lone pairs are present, as in a molecule with a trigonal pyramidal shape, the bond angles can be less than the ideal due to lone pair-bond pair (LP-BP) repulsions.