IGCSE Chemistry worksheet for Grade 9 focusing on the classification of matter using particle diagrams.

Let's solve this Classification of Matter worksheet step by step. We are given 12 diagrams showing different arrangements of atoms (represented by black and white circles). Our goal is to classify each diagram as:

- A. Elements – made of only one type of atom (same atoms bonded together).
- B. Compounds – made of molecules containing two or more *different* types of atoms chemically bonded.
- C. Mixtures of elements – a mixture of two or more pure elements (each element in its elemental form).
- D. Mixtures of compounds – a mixture of two or more compounds.
- E. Mixtures of elements and compounds – a mixture that includes both elemental forms and compound molecules.

We will analyze each diagram based on the arrangement of atoms.

---

Key:

- Black circles = one type of atom (say, Atom A)
- White circles = another type of atom (say, Atom B)

---

1)

Each molecule has one black and two white atoms → same structure everywhere → all identical molecules, each with two different atoms → Compound

✔ Answer: B. Compounds

---

2)

Randomly scattered black atoms and white atoms (single atoms), no bonding shown → Two different elements present separately → Mixture of elements

✔ Answer: C. Mixtures of elements

---

3)

There are two types of molecules:
- Some have two black atoms bonded (like O₂)
- Others have two white atoms bonded (like H₂)
→ Two different elemental molecules → Mixture of elements

✔ Answer: C. Mixtures of elements

---

4)

All molecules are identical: three black atoms and one white atom? Wait — actually, each molecule has three black atoms and one white atom? Let’s count:

Wait — looking closely: Each molecule has one white atom and three black atoms → same pattern → all molecules are identical → compound

But wait — is it only one type? Yes, all molecules are the same → Compound

✔ Answer: B. Compounds

---

5)

All particles are single black atoms → only one type of atom → Element

✔ Answer: A. Elements

---

6)

All molecules are identical: each has four black atoms arranged in a square-like pattern → same atoms → Elemental molecules (e.g., like P₄)

→ Only one type of molecule → Element

✔ Answer: A. Elements

---

7)

All molecules are two white atoms bonded together → diatomic molecules of same atom → Element

✔ Answer: A. Elements

---

8)

Contains:
- Single black atoms
- Molecules of one black + one white atom
- Also single white atoms

So we have:
- Elemental atoms (black and white)
- Compound molecules (black-white)

→ Mix of elements and compounds

✔ Answer: E. Mixtures of elements and compounds

---

9)

Contains:
- Single black atoms (element)
- Diatomic white molecules (O₂-like)
- Black-white molecules (compound)

So: elements (black and white atoms) and a compound → Mix of elements and compounds

✔ Answer: E. Mixtures of elements and compounds

---

10)

Contains:
- Diatomic white molecules (element)
- Molecules with one black and one white atom (compound)

So: Element (white) and Compound → Mix of elements and compounds

✔ Answer: E. Mixtures of elements and compounds

---

11)

All molecules are identical: each has one white and three black atoms → same structure → Compound

→ All molecules are the same → Compound

✔ Answer: B. Compounds

---

12)

Contains:
- Diatomic black molecules (e.g., N₂)
- Molecules with one black and one white atom (compound)

So: Element (black-black) and Compound → Mix of elements and compounds

✔ Answer: E. Mixtures of elements and compounds

---

✔ Final Answers:

| Number | Answer |
|--------|--------|
| 1) | B |
| 2) | C |
| 3) | C |
| 4) | B |
| 5) | A |
| 6) | A |
| 7) | A |
| 8) | E |
| 9) | E |
| 10) | E |
| 11) | B |
| 12) | E |

---

🔍 Summary Explanation:

- Elements (A): Only one type of atom (either individual or bonded into identical molecules).
- Compounds (B): Only one type of molecule, made of two or more different atoms chemically bonded.
- Mixtures of elements (C): Two or more pure elements present separately (as atoms or molecules).
- Mixtures of compounds (D): Two or more compounds mixed together.
- Mixtures of elements and compounds (E): Both elements and compounds present.

In this worksheet, no diagram shows D (mixtures of compounds) — all mixtures involve elements and/or compounds.

✔ So, D is not used in any answer.

---

Let me know if you'd like a visual explanation or printable version!