Which of the following has a bond angle of approximately 120°?

A bond angle of approximately 120° is characteristic of molecules that have a trigonal planar geometry. In the case of boron trifluoride (BH3), boron has three valence electrons and forms three covalent bonds with three chlorine atoms. The molecule has no lone pairs of electrons, leading to a planar arrangement where the three bond pairs of electrons spread out as far as possible, resulting in bond angles of about 120°.

The other options refer to molecular geometries that do not exhibit this bond angle. For example, methane (CH4) exhibits a tetrahedral geometry with bond angles of about 109.5°, due to the presence of four bond pairs and no lone pairs around the central carbon atom. Beryllium dichloride (BeCl2) has a linear geometry with bond angles of 180°, as it features two bond pairs with no lone pairs, creating a straight line. Sulfur hexafluoride (SF6) has an octahedral geometry, leading to bond angles of 90°, due to its six bond pairs around the central sulfur atom.

Therefore, the correct option is BH3, as it is the only molecule listed that has a bond angle of approximately 120° due to