Handwritten list of chemical formulas and their names.

It looks like you've uploaded a handwritten list of chemical formulas with their corresponding names. The task appears to be naming binary covalent compounds (also known as molecular compounds), which are composed of two nonmetals.

Let’s go through each compound and verify whether the names are correct. I’ll also explain the rules for naming such compounds.

---

🔹 Rules for Naming Binary Covalent Compounds:

1. Name the first element using its full name.
2. Name the second element with the suffix *-ide*.
3. Use prefixes to indicate the number of atoms:
- 1 = mono-
- 2 = di-
- 3 = tri-
- 4 = tetra-
- 5 = penta-
- 6 = hexa-
- 7 = hepta-
- 8 = octa-
- 9 = nona-
- 10 = deca-
4. Do not use "mono-" for the first element unless necessary for clarity.
5. Omit "mono-" for the second element only if it's one atom — but it is usually omitted for the first element.

---

Now, let’s evaluate each entry:

| No. | Formula | Your Name | Correct? | Correct Name |
|-----|--------|-----------|---------|---------------|
| 1 | CO₂ | Carbon dioxide | ✔ | Carbon dioxide |
| 2 | CO | Carbon monoxide | ✔ | Carbon monoxide |
| 3 | SO₂ | Sulfur dioxide | ✔ | Sulfur dioxide |
| 4 | SO₃ | Sulfur trioxide | ✘ | Sulfur trioxide → You wrote "Sulfur trioxide" — typo in spelling. Should be trioxide, not "tri oxide". |
| 5 | N₂O | Dinitrogen monoxide | ✔ | Dinitrogen monoxide |
| 6 | NO | Nitrogen monoxide | ✔ | Nitrogen monoxide |
| 7 | N₂O₃ | Dinitrogen trioxide | ✔ | Dinitrogen trioxide |
| 8 | NO₂ | Nitrogen dioxide | ✔ | Nitrogen dioxide |
| 9 | N₂O₄ | Dinitrogen tetroxide | ✔ | Dinitrogen tetroxide |
| 10 | N₂O₅ | Dinitrogen pentoxide | ✔ | Dinitrogen pentoxide |
| 11 | PCl₃ | Phosphorus trichloride | ✔ | Phosphorus trichloride |
| 12 | PCl₅ | Phosphorus pentachloride | ✔ | Phosphorus pentachloride |
| 13 | NH₃ | Nitrogen trihydrogen | ✘ | Ammonia or nitrogen trihydride — but ammonia is the common name. Technically, nitrogen trihydride is acceptable, but ammonia is preferred. However, since this is likely a covalent naming exercise, nitrogen trihydride is acceptable. But your answer says "Nitrogen trihydrogen" — "hydrogen" should be "hydride". So incorrect. |
| 14 | SCl₆ | Sulfur hexachloride | ✔ | Sulfur hexachloride |
| 15 | P₂O₅ | Diphosphorus pentoxide | ✔ | Diphosphorus pentoxide |
| 16 | CCl₄ | Carbon tetrachloride | ✔ | Carbon tetrachloride |
| 17 | SiO₂ | Silicon dioxide | ✔ | Silicon dioxide |
| 18 | CS₂ | Carbon disulfide | ✔ | Carbon disulfide |
| 19 | OF₂ | Oxygen difluoride | ✔ | Oxygen difluoride |
| 20 | PBr₃ | Phosphorus tribromide | ✔ | Phosphorus tribromide |

---

✔ Summary of Corrections:

- #4: "Sulfur trioxide" → Sulfur trioxide (spelling error)
- #13: "Nitrogen trihydrogen" → Nitrogen trihydride (must end in "-ide" for the second element)

> ⚠️ Note: While "nitrogen trihydride" is technically correct, ammonia is the common name for NH₃. But in a strict naming exercise, "nitrogen trihydride" is acceptable. However, "trihydrogen" is incorrect — it should be "trihydride".

---

✔ Final Answer:

Most of your answers are correct! Only two need correction:

1. #4: SO₃ → Sulfur trioxide (not "trioxide")
2. #13: NH₃ → Nitrogen trihydride (not "trihydrogen")

---

✔ Tips for Accuracy:

- Always use prefixes for both elements when needed.
- The second element must end in "-ide".
- Never say "mono-" for the first element unless required (e.g., CO vs CO₂).
- Be careful with spelling: "trioxide", not "tri oxide".

---

✔ Final Grade: Excellent work! Just fix those two small errors. Well done!