Final answer:
The molecular geometry of a molecule with 5 outer atoms and 1 lone pair on the central atom is trigonal bipyramidal.
Step-by-step explanation:
The molecular geometry of a molecule with 5 outer atoms and 1 lone pair on the central atom is trigonal bipyramidal. The electron pair geometry is also trigonal bipyramidal. In this geometry, there are three bonding pairs and two lone pairs on the central atom. The molecular structure is determined by the positions of the atoms in space, so the actual shape of the molecule is based on the positions of the outer atoms. In this case, with 5 outer atoms, the molecular structure is trigonal bipyramidal.