Draw the Lewis dot structure for SeO2. Determine the electron geometry of SeO2. Select Draw Rings More Erase Se O O linear tetrahedral trigonal planar. Determine the molecular geometry of SeO2. Identify the approximate bond angle in SeO2. linear 90° tetrahedral 180° bent trigonal planar trigonal pyramidal 109.50 120°.
The Correct Answer and Explanation is:
To address this question, we need to draw the Lewis dot structure of selenium dioxide (SeO₂), determine its electron geometry, molecular geometry, and bond angle.
✅ Correct Answers:
- Lewis structure: Se is the central atom, with double bonds to two oxygen atoms and one lone pair on Se.
- Electron geometry: Trigonal planar
- Molecular geometry: Bent
- Approximate bond angle: ~120°
✏️ Step-by-Step Explanation (300+ words):
1. Count valence electrons:
- Se (Group 16): 6 valence electrons
- O (Group 16): 6 valence electrons × 2 = 12
Total valence electrons = 6 (Se) + 12 (O₂) = 18 electrons
2. Choose the central atom:
- Selenium (Se) is less electronegative than oxygen, so Se is the central atom.
3. Create a skeletal structure:
- Connect Se to two O atoms with single bonds:
O — Se — O - So far, that uses 4 electrons (2 single bonds × 2 electrons = 4).
4. Distribute remaining electrons:
- 18 total electrons − 4 (bonds) = 14 electrons remaining
- Place 6 electrons (3 lone pairs) on each O atom to fulfill the octet:
- 6 × 2 = 12 electrons used
- Now we have 2 electrons left → place them as a lone pair on Se.
5. Check octet and formal charges:
- Se has:
- 2 bonding pairs (4 e⁻)
- 1 lone pair (2 e⁻)
- That’s only 6 electrons → incomplete octet
- To satisfy octet, convert one lone pair from each O into a double bond with Se:
O = Se = O .. - Now Se has:
- 2 double bonds (8 electrons)
- 1 lone pair (2 electrons)
→ Total of 10 electrons (which is acceptable for Se, as it can expand its octet being in period 4).
6. Determine electron and molecular geometry:
- Electron geometry: Based on three regions of electron density (2 bonding pairs and 1 lone pair) → Trigonal planar
- Molecular geometry: Lone pair affects the shape → Bent
7. Bond angle:
- Trigonal planar geometry typically has bond angles of ~120°. Due to the lone pair repulsion, the angle may be slightly less, but 120° is the best approximate answer.
🔍 Summary:
- Lewis Structure: O = Se: = O
- Electron Geometry: Trigonal planar
- Molecular Geometry: Bent
- Bond Angle: ~120°?