Covalent Bonding Review Sheet from December 12, 2012, featuring exercises on naming and writing formulas for covalent compounds.

It looks like you've uploaded a Covalent Bonding Review Sheet with a set of problems related to naming and writing formulas for covalent compounds. You’ve already filled in some answers, but I’ll go through each question carefully, verify the correctness, explain the reasoning, and correct any errors.

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✔ Section 1: Naming and Formula Writing

#### Part A: Write the formulas for the following covalent compounds

Let’s go through each one:

1. Nitrogen Monoxide
→ One nitrogen (N), one oxygen (O)
→ NO ✔ Correct

2. Dinitrogen Monoxide
→ "Di-" = 2 N, "mono-" = 1 O
→ N₂O ✔ Correct

3. Nitrogen Dioxide
→ One N, two O atoms
→ NO₂ ✔ Correct

4. Dinitrogen Trioxide
→ Two N, three O
→ N₂O₃ ✔ Correct

5. Dinitrogen Tetraoxide
→ Two N, four O
→ N₂O₄ ✔ Correct

6. Dinitrogen Pentaoxide
→ Two N, five O
→ N₂O₅ ✔ Correct

7. Carbon dioxide
→ One C, two O
→ CO₂ ✔ Correct

8. Phosphorus triiodide
→ One P, three I
→ PI₃ ✔ Correct

9. Sulfur dichloride
→ One S, two Cl
→ SCl₂ ✔ Correct

10. Nitrogen trifluoride
→ One N, three F
→ NF₃ ✔ Correct

✔ All answers in Part A are correct.

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#### Part B: Write names from the following formulas

Now let's analyze each formula and name it using Greek prefixes (mono-, di-, tri-, tetra-, penta-, etc.).

11. N₄F₄
→ Four N, four F
→ "Tetra" for both
→ Tetranitrogen tetrafluoride
✘ Your answer: *dinitrogen tetrafluoride* → Incorrect
✔ Correct: Tetranitrogen tetrafluoride

> Note: While less common, this compound is named using prefixes for both elements. The prefix "di-" means two, so "dinitrogen" implies only 2 N atoms — not 4.

12. SCl₄
→ One S, four Cl
→ "Tetrachloride"
→ Sulfur tetrachloride ✔ Correct

13. ClF₃
→ One Cl, three F
→ Chlorine trifluoride ✔ Correct

14. SiO₂
→ One Si, two O
→ Silicon dioxide ✔ Correct

15. P₄O₁₀
→ Four P, ten O
→ "Tetraphosphorus decaoxide"
✔ Correct

> Note: This is a common compound (phosphorus pentoxide), but its molecular form is P₄O₁₀, so we use the actual atom count.

16. SiF₄
→ One Si, four F
→ Silicon tetrafluoride ✔ Correct

17. H₂O
→ Two H, one O
→ Di-hydrogen monoxide
→ But commonly called water, but in covalent naming system:
→ Dihydrogen monoxide ✔ Correct

18. Br₂
→ Elemental bromine
→ Just bromine
→ But since it's a diatomic molecule, we can say dibromine
→ However, elemental forms are usually just named as the element: bromine
✔ Both "dibromine" or "bromine" are acceptable, but "bromine" is standard.

19. HBr
→ Hydrogen bromide (covalent compound between H and Br)
→ Hydrogen bromide ✔ Correct

20. N₂S₃
→ Two N, three S
→ Dinitrogen trisulfide
→ Your answer: *dinitrogen trisulfide* ✔ Correct

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✔ Summary of Corrections

| Question | Your Answer | Correct Answer | Notes |
|--------|-------------|----------------|-------|
| 11. N₄F₄ | dinitrogen tetrafluoride | tetranitrogen tetrafluoride | Must reflect actual number of atoms |
| 18. Br₂ | dibromide or bromine | bromine | Standard name; "dibromine" is informal |

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🔍 Key Rules Recap:

- Use Greek prefixes for all elements in covalent compounds.
- Prefixes: mono- (1), di- (2), tri- (3), tetra- (4), penta- (5), hexa- (6), hepta- (7), octa- (8), nona- (9), deca- (10).
- "Mono-" is often omitted for the first element (e.g., CO is carbon monoxide, not monocarbon monoxide).
- For elemental molecules like Br₂, we just call it bromine unless specifying the molecule (e.g., "diatomic bromine").
- Hydrogen halides (like HBr) are named as hydrogen + halide (e.g., hydrogen bromide).

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✔ Final Answers (Corrected):

1. NO
2. N₂O
3. NO₂
4. N₂O₃
5. N₂O₄
6. N₂O₅
7. CO₂
8. PI₃
9. SCl₂
10. NF₃

11. Tetranitrogen tetrafluoride
12. Sulfur tetrachloride
13. Chlorine trifluoride
14. Silicon dioxide
15. Tetraphosphorus decaoxide
16. Silicon tetrafluoride
17. Dihydrogen monoxide
18. Bromine (or dibromine)
19. Hydrogen bromide
20. Dinitrogen trisulfide

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Let me know if you'd like a printable version or help with Section 2!