This chemistry worksheet provides 20 practice problems for identifying and naming ionic and covalent compounds.

Final Answer:
1) Ionic – Sodium carbonate
2) Covalent – Tetraphosphorus decoxide
3) Covalent – Dinitrogen pentoxide
4) Ionic – Iron(II) sulfate
5) Covalent – Silicon dioxide
6) Ionic – Iron(III) chloride
7) Ionic – Cobalt(II) bromide
8) Covalent – Diboron tetrahydride
9) Covalent – Carbon monoxide
10) Covalent – Phosphorus trichloride
11) Covalent – N₂O₃
12) Covalent – NO₂
13) Covalent – SCl₅ (Note: common name “sulfur pentoxide” is incorrect; correct is sulfur pentachloride or disulfur decaoxide — but based on naming, likely meant SCl₅ for practice)
14) Ionic – LiC₂H₃O₂
15) Covalent – PF₃
16) Ionic – V₂O₅
17) Ionic – Al(OH)₃
18) Ionic – ZnS
19) Covalent – SiF₄
20) Ionic – Ag₃PO₄

(Note: For #13, “sulfur pentoxide” is not a standard compound. The most likely intended compound is “sulfur pentachloride” (SCl₅) or “diphosphorus pentoxide” (P₂O₅). Since the name says “sulfur pentoxide,” and no such stable compound exists, it’s likely a typo. In educational contexts, students are often asked to write formulas based on given names even if they’re not real. So we follow the naming pattern: sulfur + pentoxide → S₁O₅ → SO₅, but that’s unstable. Better to assume it was meant to be “sulfur trioxide” (SO₃) or “phosphorus pentoxide” (P₂O₅). However, since the task says “sulfur pentoxide,” we’ll go with SO₅ for the sake of matching the name, even though it’s not real. Alternatively, some teachers accept S₂O₅ as a made-up form. But to stay consistent with naming rules, we’ll use SO₅.)

Actually, let’s fix this: “sulfur pentoxide” is not a real compound. The closest real one is “sulfur trioxide” (SO₃). But since the problem says “sulfur pentoxide,” and we must follow instructions, we’ll write the formula as if it were named correctly: sulfur (S) + pentoxide (5 oxygens) = SO₅.

But wait — in reality, “pentoxide” usually refers to 5 oxygen atoms bonded to two atoms, like P₂O₅. So maybe it’s a mistake and should be “dinitrogen trioxide” or something else. Since this is a practice sheet, we’ll assume it’s asking for SO₅, even though it doesn’t exist.

Alternatively, many textbooks list “sulfur pentoxide” as a trick question or error. To avoid confusion, I’ll use the most logical interpretation: if it says “sulfur pentoxide,” write SO₅ — even if it’s not real — because that’s what the naming rules would produce.

So final answer for #13: Covalent – SO₅

But to be safe and educational, let me note: This compound doesn’t actually exist. Real sulfur oxides are SO₂ and SO₃. But for homework, we follow the naming rule.

✔ Final corrected answers:

1) Ionic – Sodium carbonate
2) Covalent – Tetraphosphorus decoxide
3) Covalent – Dinitrogen pentoxide
4) Ionic – Iron(II) sulfate
5) Covalent – Silicon dioxide
6) Ionic – Iron(III) chloride
7) Ionic – Cobalt(II) bromide
8) Covalent – Diboron tetrahydride
9) Covalent – Carbon monoxide
10) Covalent – Phosphorus trichloride
11) Covalent – N₂O₃
12) Covalent – NO₂
13) Covalent – SO₅ *(Note: Not a real compound; likely meant SO₃ or P₂O₅)*
14) Ionic – LiC₂H₃O₂
15) Covalent – PF₃
16) Ionic – V₂O₅
17) Ionic – Al(OH)₃
18) Ionic – ZnS
19) Covalent – SiF₄
20) Ionic – Ag₃PO₄