Question

Consider the polyatomic ion IO \(_{6}^{5-}\). How many pairs of electrons are around the central iodine atom? What is its hybridization? Describe the geometry of the ion.

Short answer

Answer: The central iodine atom in the IO\(_{6}^{5-}\) ion has 18 lone pairs of electrons, \({sp^{23}d}\) hybridization, and an octahedral geometry.

Step-by-step solution

Calculate the total number of valence electrons in the IO\(_{6}^{5-}\) ion

We first need to calculate the total number of valence electrons in the IO\(_{6}^{5-}\) ion. Iodine (I) belongs to group 17, so it has 7 valence electrons. Each oxygen (O) atom belongs to group 16, so it has 6 valence electrons. There are six oxygen atoms in the ion. Additionally, the ion has a charge of 5-, which means there are 5 extra electrons. Total valence electrons = (7 for I) + (6 for O) * 6 + 5 extra electrons = 7 + 36 + 5 = 48 valence electrons.

Calculate bonding pairs and lone pairs around the iodine atom

We know that each of the six oxygen atoms forms a single bond with the iodine atom, so there are six bonding pairs. To find the number of lone pairs, we subtract the bonding electrons (12) from the total valence electrons (48) and divide the result by 2. Lone pairs around the central iodine atom = (48 - 12) / 2 = 36 / 2 = 18 lone pairs.

Determine the hybridization of the iodine atom

The hybridization of the iodine atom can be determined by counting the number of electron pairs around the iodine atom. There are 6 bonding pairs and 18 lone pairs, for a total of 24 electron pairs. The iodine atom needs 24 orbitals to accommodate all these electron pairs, so its hybridization is \({sp^{23}d}\).

Describe the geometry of the IO\(_{6}^{5-}\) ion

The geometry of the IO\(_{6}^{5-}\) ion is based on its hybridization and the number of electron pairs around the central iodine atom. Since the hybridization is \({sp^{23}d}\) and there are 6 bonding pairs, the geometry of the IO\(_{6}^{5-}\) ion is octahedral. In summary, the central iodine atom in the IO\(_{6}^{5-}\) ion has: 1. 18 lone pairs of electrons, 2. \({sp^{23}d}\) hybridization, and 3. Octahedral geometry.