Answer:
Step-by-step explanation:
I_3^−
The triiodide ion, I3−, is a polyatomic anion composed of three iodine atoms. It has a central iodine atom, which is surrounded by two other iodine atoms in a trigonal planar geometry. The hybridization of the central atom is sp2. This is because the central atom has 3 electron pairs in its valence shell, which means it needs to form three bonds with the other atoms. This requires the central atom to use one s-orbital and two p-orbitals to form three sp2 hybrid orbitals. These three sp2 orbitals are then used to form the three bonds with the other two iodine atoms, resulting in a trigonal planar geometry.