Draw a Lewis structure for SeF2O in which all atoms obey the octet rule. Do not draw double bonds to oxygen unless they are needed in order for the central atom to obey the octet rule.
The Correct Answer and Explanation is:
Correct Lewis Structure of SeF₂O:
- Central atom: Selenium (Se)
- Attached atoms: Two fluorine (F) atoms and one oxygen (O) atom
- Total valence electrons:
- Se (Group 16): 6 electrons
- F (Group 17): 7 electrons × 2 = 14 electrons
- O (Group 16): 6 electrons
Total = 6 + 14 + 6 = 26 valence electrons
Steps to draw the Lewis structure:
- Place Se in the center, with F, F, and O bonded to it using single bonds.
- Three single bonds use up 6 electrons (3 bonds × 2 electrons = 6).
- Subtract used electrons:
26 total – 6 = 20 electrons remaining - Distribute remaining electrons to complete octets:
- Each fluorine needs 6 more electrons (already sharing 2 with Se):
6 × 2 = 12 electrons - Oxygen also needs 6 more electrons to complete its octet:
6 electrons
12 (for both Fs) + 6 (for O) = 18 electrons used
- Each fluorine needs 6 more electrons (already sharing 2 with Se):
- Remaining electrons: 20 – 18 = 2 electrons left
- Place the final lone pair on Se. Now Se has:
- Three bonding pairs (3 × 2 = 6 electrons)
- One lone pair (2 electrons)
Total = 8 electrons → satisfies the octet
Final Structure:
- Se is the central atom
- Single bonds to:
- Two F atoms (each with 3 lone pairs)
- One O atom (with 3 lone pairs)
- One lone pair on Se
rCopyEdit ..
:F:
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.. .. ..
:F–Se–O:
.. ..
Explanation:
This structure follows the octet rule for all atoms. Se is surrounded by 8 electrons (three bonds plus one lone pair). Both F and O complete their octets with lone pairs. No double bond is necessary to oxygen because Se already has an octet. Se does not need to expand its octet in this case, making the single bonds appropriate for a valid Lewis structure.
