Hybridization of the central atom in the hydrogen sulfide (H2S) molecule? What is the?
The Correct Answer and Explanation is:
The correct answer is sp³.
Explanation
To determine the hybridization of the central atom in a molecule, one must follow a systematic approach based on its electronic structure.
- Identify the Central Atom: In the hydrogen sulfide (H₂S) molecule, sulfur (S) is the central atom because it is the least electronegative element (excluding hydrogen, which can only form one bond).
- Determine the Lewis Structure:
- First, calculate the total number of valence electrons. Sulfur is in Group 16 of the periodic table, so it has 6 valence electrons. Each hydrogen atom (Group 1) has 1 valence electron.
Total valence electrons = 6 (from S) + 2 × 1 (from H) = 8 electrons. - Next, draw the skeletal structure with the central sulfur atom single-bonded to two hydrogen atoms. This uses 4 electrons (2 bonds × 2 electrons/bond).
- Distribute the remaining 4 electrons (8 – 4) as lone pairs on the central sulfur atom to satisfy its octet. This results in two lone pairs on the sulfur atom.
- First, calculate the total number of valence electrons. Sulfur is in Group 16 of the periodic table, so it has 6 valence electrons. Each hydrogen atom (Group 1) has 1 valence electron.
The Lewis structure is: H–S̈–H (with two lone pairs on S).
- Find the Steric Number: The hybridization of the central atom can be predicted by its steric number. The steric number is the total number of electron domains around the central atom. An electron domain can be a single bond, a double bond, a triple bond, or a lone pair.
- Number of atoms bonded to the central sulfur atom = 2 (two H atoms)
- Number of lone pairs on the central sulfur atom = 2
- Assign Hybridization: The steric number corresponds directly to the number of hybrid orbitals required.
- A steric number of 2 corresponds to sp hybridization.
- A steric number of 3 corresponds to sp² hybridization.
- A steric number of 4 corresponds to sp³ hybridization.
- A steric number of 5 corresponds to sp³d hybridization.
Since the steric number for the sulfur atom in H₂S is 4, it requires four hybrid orbitals. These are formed by mixing one s orbital and three p orbitals, resulting in sp³ hybridization. This hybridization leads to a tetrahedral electron geometry, but because two of the domains are lone pairs, the molecular geometry is bent.thumb_upthumb_down
