Draw the Lewis structure for ICl3

Draw the Lewis structure for ICl₃. What is the hybridization on the I (iodine) atom?

The correct answer and explanation is :

Lewis Structure of ICl₃

To draw the Lewis structure for iodine trichloride (ICl₃), we need to follow several steps:

1. Count the total valence electrons:

• Iodine (I) is in Group 17 of the periodic table and has 7 valence electrons.
• Chlorine (Cl) is also in Group 17 and each chlorine atom has 7 valence electrons.
• Total valence electrons = (1 × 7) + (3 × 7) = 28 valence electrons.

1. Arrange the atoms:

• Iodine is the central atom because it is less electronegative than chlorine.
• Draw iodine in the center and place the three chlorine atoms around it.

1. Form bonds:

• Place a single bond (2 electrons) between iodine and each chlorine atom.

1. Distribute the remaining electrons:

• After placing the bonds, there are 28 – 6 = 22 electrons remaining.
• Assign the remaining electrons to chlorine atoms to complete their octets (6 electrons around each chlorine atom, in addition to the 2 electrons already involved in the bond).
• The remaining 2 electrons will be placed on iodine as lone pairs.

1. Check for formal charges:

• Each chlorine atom has 3 lone pairs, and iodine has 2 lone pairs. The formal charge on iodine is 0, and each chlorine atom also has a formal charge of 0.

Lewis Structure Diagram:

        Cl
        |
    Cl—I—Cl
        |
       (lone pairs on I)

Hybridization of Iodine (I) Atom:

The iodine atom in ICl₃ has 2 lone pairs and 3 bonding pairs (one with each chlorine). This means that iodine has a total of 5 electron pairs (2 lone pairs + 3 bonding pairs).

In the case of 5 electron pairs, the molecular geometry is trigonal bipyramidal. The hybridization of iodine is sp³d because it uses one d-orbital in addition to s and p orbitals to accommodate the five electron pairs.

Explanation:

• Electron Pair Geometry: Iodine has 5 electron pairs (3 bonding and 2 lone pairs), which results in a trigonal bipyramidal electron geometry.
• Molecular Geometry: Since there are two lone pairs, they will occupy equatorial positions (because these positions are more spacious), and the bonding pairs of chlorine atoms will occupy the remaining positions. This leads to a T-shaped molecular geometry.
• Hybridization: Iodine’s hybridization is sp³d because it forms five hybrid orbitals, one from the s orbital, three from the p orbitals, and one from the d orbital, which allow it to accommodate five electron pairs.

Thus, ICl₃ has a trigonal bipyramidal electron geometry, with a T-shaped molecular geometry, and iodine undergoes sp³d hybridization.