How many lone pairs in the lewis dot structure of SiS2
The Correct Answer and Explanation is:
To determine how many lone pairs are in the Lewis dot structure of SiS (silicon monosulfide), we first need to follow proper steps for drawing the structure.
Step 1: Determine the total number of valence electrons.
- Silicon (Si) is in group 14, so it has 4 valence electrons.
- Sulfur (S) is in group 16, so it has 6 valence electrons.
Since there is one silicon atom and one sulfur atom:
- Total valence electrons = 4 (from Si) + 6 (from S) = 10 valence electrons
Step 2: Choose the central atom.
Silicon is less electronegative than sulfur, so Si will be the central atom.
Step 3: Form a bond between Si and S.
- Draw a single bond between Si and S, which uses 2 electrons.
- Remaining electrons = 10 – 2 = 8 electrons
Step 4: Distribute the remaining electrons to satisfy the octet rule.
- Place lone pairs around the more electronegative atom first, which is sulfur.
- Give sulfur 3 lone pairs (6 electrons). That leaves 2 electrons.
- Place the remaining 2 electrons as a lone pair on silicon.
Now:
- Sulfur has 3 lone pairs (6 electrons) and shares 2 electrons in a bond = 8 electrons total.
- Silicon has 1 lone pair (2 electrons) and shares 2 electrons in the bond = only 4 electrons.
Silicon does not have a complete octet, so we try a double bond between Si and S:
- This means 4 electrons are used in bonding.
- Then, sulfur needs only 2 lone pairs (4 electrons), and silicon can have 1 lone pair (2 electrons).
- Total used: 4 (bonding) + 4 (S lone pairs) + 2 (Si lone pair) = 10 electrons.
Final Structure:
- Si and S share a double bond.
- Si has 1 lone pair.
- S has 2 lone pairs.
Answer:
There are 3 lone pairs in total in the Lewis dot structure of SiS.
Explanation:
The Lewis structure of SiS includes a double bond between silicon and sulfur. Sulfur, being more electronegative, holds 2 lone pairs to complete its octet. Silicon, with fewer valence electrons, holds 1 lone pair. Together, these account for 3 lone pairs, and all 10 valence electrons are properly assigned. This structure satisfies the octet rule for sulfur and gives a stable configuration for both atoms
