Question

In each of the following polyatomic ions, the central atom has an expanded octet. Determine the number of electron pairs around the central atom and the hybridization in (a) \(\mathrm{SF}_{2}^{2-}\) (b) \(\mathrm{AsCl}_{6}^{-}\) (c) \(\mathrm{SCl}_{4}^{2-}\)

Short answer

Question: Determine the hybridization of the central atom in each of the following ions: (a) \(\mathrm{SF}_{2}^{2-}\), (b) \(\mathrm{AsCl}_{6}^{-}\), and (c) \(\mathrm{SCl}_{4}^{2-}\). Answer: The hybridization of the central atom for each ion is as follows: (a) \(\mathrm{sp^{10}}\), (b) \(\mathrm{sp^{23}}\), and (c) \(\mathrm{sp^{17}}\).

Step-by-step solution

Determine the central atom

In this case, the central atom is S (Sulfur).

Count the valence electrons

Sulfur has 6 valence electrons and each Fluorine has 7 valence electrons. Since there are two F atoms and the ion has a 2- charge, the total number of valence electrons is: $$6 + 2(7) + 2 = 22$$

Calculate the number of electron pairs

Divide the total valence electrons by 2 to get the number of electron pairs: $$\frac{22}{2} = 11$$

Determine the hybridization

With 11 electron pairs, the hybridization is \(\mathrm{sp^{10}}\). (b) \(\mathrm{AsCl}_{6}^{-}\)

Determine the central atom

In this case, the central atom is As (Arsenic).

Count the valence electrons

Arsenic has 5 valence electrons, and each Chlorine has 7 valence electrons. Since there are six Cl atoms and the ion has a 1- charge, the total number of valence electrons is: $$5 + 6(7) + 1 = 48$$

Calculate the number of electron pairs

Divide the total valence electrons by 2 to get the number of electron pairs: $$\frac{48}{2} = 24$$

Determine the hybridization

With 24 electron pairs, the hybridization is \(\mathrm{sp^{23}}\). (c) \(\mathrm{SCl}_{4}^{2-}\)

Determine the central atom

In this case, the central atom is S (Sulfur).

Count the valence electrons

Sulfur has 6 valence electrons, and each Chlorine has 7 valence electrons. Since there are four Cl atoms and the ion has a 2- charge, the total number of valence electrons is: $$6 + 4(7) + 2 = 36$$

Calculate the number of electron pairs

Divide the total valence electrons by 2 to get the number of electron pairs: $$\frac{36}{2} = 18$$

Determine the hybridization

With 18 electron pairs, the hybridization is \(\mathrm{sp^{17}}\).