Final answer:
The electron-pair geometry of ICl₃ is trigonal bipyramidal and the molecular geometry is T-shaped; the answer is a. eg = trigonal bipyramidal, mg = T-shaped.
Step-by-step explanation:
To determine the electron geometry (eg) and molecular geometry (mg) of ICl₃, we need to analyze the regions of electron density around the iodine atom, which acts as the central atom. ICl₃ has 7 valence electrons from iodine and 7 from each of the three chlorine atoms, for a total of 28 valence electrons. After accounting for the I-Cl bonds, there are 2 lone pairs on the iodine.
The electron-pair geometry for a molecule with five regions of electron density (– three bonding pairs and two lone pairs) is trigonal bipyramidal. The molecular geometry, which is determined by the positions of the atoms, is T-shaped because the lone pairs occupy two of the equatorial positions, pushing the three chlorine atoms to the corners of a T. Hence, the correct answer is a. eg = trigonal bipyramidal, mg = T-shaped.