Final answer:
Using VSEPR theory, the IF2- ion with five electron groups around the central iodine atom (two bonding pairs and three lone pairs) adopts a trigonal bipyramidal electron group arrangement, leading to a bent molecular shape.
Step-by-step explanation:
Using VSEPR theory to predict the electron group arrangement around the central atom in the ion IF2-, you must first determine the number of electron groups around the central atom. In this case, there are five electron groups around iodine consisting of two bonding pairs with the fluorine atoms and three lone pairs. The VSEPR model suggests that to minimize repulsions between these electron groups, they will adopt an arrangement that places them at the corners of a trigonal bipyramid.
This arrangement leads to a molecular structure with the central atom at the apex and lone pairs occupying the equatorial positions to minimize repulsions. It's important to note that the actual shape of the molecule takes into account only the atoms and not the lone pairs of electrons. Therefore, taking the two iodine-fluorine bonds and ignoring the lone pairs, the shape is described as bent or V-shaped.