In ammonia, a central nitrogen atom is bonded to three hydrogen atoms. similarly, boron trifluoride has a central boron atom bonded to three fluorine atoms. however, ammonia is pyramidal and boron trifluoride is trigonal planar in shape. which statement justifies this difference in their structure? the lone pair of electrons in boron trifluoride increases the bond angle between the bonding pairs, giving it a planar structure. the lone pair of electrons in boron trifluoride decreases the bond angle between the bonding pairs, giving it a planar structure. the lone pair of electrons in boron trifluoride stabilizes the bond angle between the bonding pairs, giving it a planar structure. the lone pair of electrons in ammonia increases the bond angle between the bonding pairs, giving it a pyramidal structure. the lone pair of electrons on the nitrogen in ammonia decreases the bond angle between the bonding pairs, giving it a pyramidal structure.