Draw the electron dot formula for silicon disulfide, 5152. How many pairs of nonbonding electrons are in a silicon disulfide molecule? 02 06 01 hone of the above G4
The Correct Answer and Explanation is :
To draw the electron dot structure (also known as the Lewis structure) for silicon disulfide (SiS₂), we follow these steps:
Step 1: Count the valence electrons
- Silicon (Si) is in group 14 of the periodic table, so it has 4 valence electrons.
- Sulfur (S) is in group 16, so each sulfur atom has 6 valence electrons.
Thus, for SiS₂:
- Silicon has 1 × 4 = 4 valence electrons.
- Sulfur has 2 × 6 = 12 valence electrons.
The total number of valence electrons = 4 (from Si) + 12 (from S) = 16 valence electrons.
Step 2: Sketch the skeleton structure
- The silicon atom will be the central atom since it is less electronegative than sulfur.
- Place two sulfur atoms around the silicon atom, and form single bonds between silicon and sulfur. This uses 2 electrons (1 for each bond).
Step 3: Distribute remaining electrons
- After forming the bonds, 16 electrons – 2 electrons used in the bonds = 14 electrons remain.
- Distribute the remaining electrons as lone pairs around the sulfur atoms first, as sulfur is more electronegative than silicon.
- Each sulfur atom needs 6 more electrons to complete its octet (as each already shares 1 electron with silicon).
- Place 3 lone pairs (6 electrons) around each sulfur atom. This uses up all 12 remaining electrons.
Step 4: Check the structure
- The silicon atom now has 2 electrons from each bond (total 4 electrons), which satisfies its octet.
- Each sulfur atom has 6 electrons from lone pairs and 2 electrons from the bond with silicon, fulfilling its octet.
Electron Dot Formula
The electron dot structure for silicon disulfide is:
:S: :S:
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Si- Each sulfur atom has 3 lone pairs of electrons and shares 1 pair with silicon, completing its octet.
- Silicon shares 2 pairs of electrons, completing its octet.
Number of Nonbonding Electron Pairs
In the silicon disulfide molecule, the nonbonding electrons are those on the sulfur atoms. Each sulfur atom has 3 lone pairs, for a total of 6 lone pairs of electrons.
Thus, the answer is 6 pairs of nonbonding electrons.