Naming Ionic Compounds with Polyatomic Ions online exercise for ... - Free Printable

Let's solve this step by step.

---

Part 1: Identify the polyatomic ions

Polyatomic ions are charged species made up of two or more atoms covalently bonded together. They are often memorized as common ions.

We need to mark an (x) beside each formula that is a polyatomic ion.

| Ion | Is it polyatomic? |
|------------|-------------------|
| Fe³⁺ | No |
| NO₃⁻ | Yes (x) |
| PO₄³⁻ | Yes (x) |
| SO₄²⁻ | Yes (x) |
| Be²⁺ | No |
| Cl⁻ | No |
| OH⁻ | Yes (x) |
| S²⁻ | No |
| NH₄⁺ | Yes (x) |
| O²⁻ | No |

✔ So, the polyatomic ions are:
- NO₃⁻
- PO₄³⁻
- SO₄²⁻
- OH⁻
- NH₄⁺

Mark them with an (x):

```
Fe³⁺ NO₃⁻ (x)
PO₄³⁻ (x) SO₄²⁻ (x)
Be²⁺ Cl⁻
OH⁻ (x) S²⁻
NH₄⁺ (x) O²⁻
```

---

Part 2: Name the ionic compounds

Now, name each compound using standard naming rules:

1. (NH₄)₂CO₃
- NH₄⁺ = ammonium (polyatomic cation)
- CO₃²⁻ = carbonate (polyatomic anion)
→ Ammonium carbonate

2. Al₂(SO₄)₃
- Al³⁺ = aluminum
- SO₄²⁻ = sulfate
→ Aluminum sulfate

3. AgCN
- Ag⁺ = silver (always +1)
- CN⁻ = cyanide (polyatomic ion)
→ Silver cyanide

4. Ba(ClO₃)₂
- Ba²⁺ = barium
- ClO₃⁻ = chlorate
→ Barium chlorate

5. Cu(OH)₂
- Cu²⁺ = copper(II) (since OH⁻ is –1, and there are two, so Cu must be +2)
- OH⁻ = hydroxide
→ Copper(II) hydroxide

6. Cr₂(SO₄)₃
- Cr³⁺ = chromium(III) (SO₄²⁻ is –2, three of them = –6; two Cr = +6 → each Cr = +3)
- SO₄²⁻ = sulfate
→ Chromium(III) sulfate

7. Ca(NO₃)₂
- Ca²⁺ = calcium
- NO₃⁻ = nitrate
→ Calcium nitrate

8. K₂CO₃
- K⁺ = potassium
- CO₃²⁻ = carbonate
→ Potassium carbonate

9. CaSO₄
- Ca²⁺ = calcium
- SO₄²⁻ = sulfate
→ Calcium sulfate

10. Sn₃(PO₄)₂
- Sn⁴⁺ = tin(IV) (PO₄³⁻ is –3, two of them = –6; three Sn = +6 → each Sn = +2? Wait — let's check:
Total negative charge: 2 × (–3) = –6
So total positive charge from Sn = +6
Three Sn atoms → each has +2 charge → Sn²⁺
But Sn can be +2 or +4. Since we have Sn²⁺, it's tin(II)
→ Tin(II) phosphate

> Note: Tin commonly forms both Sn²⁺ and Sn⁴⁺. The oxidation state must be determined from the anion charge.

---

✔ Final Answers:

#### Part 1: Mark polyatomic ions with (x)

| Fe³⁺ | NO₃⁻ (x) |
|----------|----------|
| PO₄³⁻ (x)| SO₄²⁻ (x)|
| Be²⁺ | Cl⁻ |
| OH⁻ (x) | S²⁻ |
| NH₄⁺ (x)| O²⁻ |

---

#### Part 2: Names of Ionic Compounds

1. (NH₄)₂CO₃ → Ammonium carbonate
2. Al₂(SO₄)₃ → Aluminum sulfate
3. AgCN → Silver cyanide
4. Ba(ClO₃)₂ → Barium chlorate
5. Cu(OH)₂ → Copper(II) hydroxide
6. Cr₂(SO₄)₃ → Chromium(III) sulfate
7. Ca(NO₃)₂ → Calcium nitrate
8. K₂CO₃ → Potassium carbonate
9. CaSO₄ → Calcium sulfate
10. Sn₃(PO₄)₂ → Tin(II) phosphate

---

Let me know if you'd like a printed version or explanation for any specific compound!