Final answer:
SO₂ has a bent molecular geometry due to one lone pair and two bonding pairs on the central sulfur atom, while NO₃⁻ has a trigonal planar geometry with no lone pairs and three bonding electron pairs around the central nitrogen atom.
Step-by-step explanation:
The molecular geometries of SO₂ and NO₃⁻ can be determined by looking at the arrangement of the electron pairs around their central atoms based on the VSEPR theory.For SO₂, sulfur is the central atom with one lone pair and two bonding pairs of electrons, which results in a bent or angular molecular geometry. In contrast, the NO₃⁻ ion has a nitrogen atom with no lone pairs and three bonding pairs, giving it a trigonal planar geometry.