Decide whether the Lewis structure proposed for each molecule is reasonable [Free] B113
Decide whether the Lewis structure proposed for each molecule is reasonable or not. Yes, it’s a reasonable structure. No, the total number of valence electrons is wrong. The correct number is: No, some atoms have the wrong number of electrons around them. The symbols of the problem atoms are: Yes, it’s a reasonable structure. No, the total number of valence electrons is wrong. The correct number is: No, some atoms have the wrong number of electrons around them. The symbols of the problem atoms are: Yes, it’s a reasonable structure. No, the total number of valence electrons is wrong. The correct number is: No, some atoms have the wrong number of electrons around them. The symbols of the problem atoms are:
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Answer
Reasonability of Lewis Structures: ClF₃, PO₄³⁻, and BeH₂
This article analyzes whether the given Lewis structures of ClF₃ (Chlorine Trifluoride), PO₄³⁻ (Phosphate ion), and BeH₂ (Beryllium Hydride) are reasonable, based on the correct distribution of valence electrons and the octet rule or exceptions.
1. ClF₃ (Chlorine Trifluoride)
Total Valence Electrons:
- Cl = 7 electrons
- F = 7 electrons × 3 = 21 electrons
- Total = 28 electrons
Chlorine is shown with only 6 electrons, while it can have an expanded octet (10 electrons).
Conclusion: Not reasonable. Incorrect number of electrons around Cl and one F atom.
2. PO₄³⁻ (Phosphate Ion)
Total Valence Electrons:
- P = 5 electrons
- O = 6 electrons × 4 = 24 electrons
- Charge (-3) = 3 electrons
- Total = 32 electrons
Conclusion: Not reasonable. Incorrect number of electrons assigned to P.
3. BeH₂ (Beryllium Hydride)
Total Valence Electrons:
- Be = 2 electrons
- H = 1 electron × 2 = 2 electrons
- Total = 4 electrons
Conclusion: Not reasonable. Wrong number of electrons shown around Be. Total valence electron count is also incorrect.
🔚 Summary Table
| Molecule/Ion | Reasonability | Total Valence Electrons | Problematic Atom(s) | Issue |
|---|---|---|---|---|
| ClF₃ | Not Reasonable | 28 | F, Cl | Incorrect number of electrons around atoms |
| PO₄³⁻ | Not Reasonable | 32 | P | Wrong electron assignment to phosphorus |
| BeH₂ | Not Reasonable | 4 | Be | Incorrect number of electrons around Be |
📘 Final Explanation:
A Lewis structure is considered reasonable only if:
- The total number of electrons matches the calculated valence electrons (considering charge).
- The bonding and non-bonding pairs are correctly shown.
- Octet rule is followed, or exceptions (like for Be and P) are correctly handled.