Since the image you've uploaded is a worksheet titled
"KS3 Chemistry: Worksheet Two – What are compounds?", and it contains diagrams labeled A through F, each showing different arrangements of atoms (represented by circles of various colors and patterns), the task likely involves identifying which diagrams represent
elements,
compounds, or
mixtures.
Let’s analyze each diagram based on the definitions:
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🔬 Key Definitions:
-
Element: A substance made of only one type of atom.
-
Compound: A substance made of two or more different types of atoms chemically bonded together in a fixed ratio.
-
Mixture: A combination of two or more substances that are not chemically bonded and can be separated physically.
---
Now let's examine each diagram:
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🔹 Diagram A
- Contains
black circles and
white circles scattered randomly.
- No bonding shown — just individual atoms.
- There are
two different types of atoms (black and white).
- They are
not chemically bonded — just mixed together.
✔ Conclusion: This is a
mixture of two elements.
---
🔹 Diagram B
- All molecules are made of
one white atom + one black atom.
- Each molecule is identical.
- The atoms are
chemically bonded (shown as connected pairs).
- Only
one type of molecule present.
✔ Conclusion: This is a
compound (e.g., like H₂O if white = H, black = O).
---
🔹 Diagram C
- Molecules consist of
one white atom + one dotted circle atom.
- All molecules are identical.
- Atoms are bonded together.
✔ Conclusion: This is a
compound (different from B because the atoms are different types).
---
🔹 Diagram D
- All particles are
pairs of black atoms.
- Only
one type of atom involved.
- Molecules are diatomic (like O₂ or N₂).
✔ Conclusion: This is an
element (diatomic molecule of the same element).
---
🔹 Diagram E
- Contains
two types of molecules:
- One is
white + black (like in B)
- Another is
white + dotted (like in C)
- Both are chemically bonded but different.
- These are
two different compounds.
✔ Conclusion: This is a
mixture of two compounds.
---
🔹 Diagram F
- Only
black circles, all identical.
- No bonding shown — just individual atoms.
- Only
one type of atom.
✔ Conclusion: This is an
element (in atomic form).
---
✔ Final Answers (likely expected):
| Diagram | Type |
|--------|------|
| A | Mixture of two elements |
| B | Compound |
| C | Compound |
| D | Element (diatomic) |
| E | Mixture of two compounds |
| F | Element (atomic) |
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📝 Summary:
-
Compounds are shown when
identical molecules contain
two or more different atoms chemically bonded (B, C).
-
Elements are shown when
only one type of atom is present (D, F).
-
Mixtures involve
more than one substance not chemically bonded (A, E).
> 💡 Remember: A compound is
not a mixture — it has a fixed composition and the atoms are chemically bonded.
If the worksheet asks questions like:
- "Which shows a compound?"
→ Answer:
B and C
- "Which shows a mixture?"
→ Answer:
A and E
- "Which shows an element?"
→ Answer:
D and F
Let me know if you'd like help answering specific questions on the next page (overleaf).
Parent Tip: Review the logic above to help your child master the concept of element or compound worksheet.
