Classify atoms, molecules, elements, and compounds worksheet ... - Free Printable

To classify the particle diagrams, we need to determine what each diagram represents in terms of matter states (solid, liquid, gas) and types of substances (element, compound, mixture). Let's analyze each one step by step.

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🔍 Key Concepts:

- Element: Made of only one type of atom.
- Compound: Made of two or more different types of atoms chemically bonded.
- Mixture: Two or more substances physically combined (not chemically bonded).
- Solid: Particles are tightly packed in a fixed arrangement; vibrating in place.
- Liquid: Particles are close but can move past each other; no fixed shape.
- Gas: Particles are far apart, moving freely.
- Pure substance: Either an element or compound.
- Homogeneous vs Heterogeneous Mixture: Uniform vs non-uniform distribution.

Let’s go through each diagram:

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1)

- Shows molecules made of black, red, and white spheres.
- Each molecule has one black, two red, and one white atom → likely H₂CO₃ or similar (e.g., carbonic acid).
- All molecules are identical, so it's a pure compound.
- Particles are close together but not in a rigid structure → liquid state?
- However, they are not arranged in a regular pattern → not solid.
- But particles are not far apart → not gas.
- So this is a liquid compound.

✔ Classification: Liquid compound

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2)

- All particles are yellow spheres, uniformly packed in a regular lattice.
- No variation in color → all same atoms.
- Fixed positions → solid state.

✔ Classification: Solid element

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3)

- Red spheres, all identical, spread out with space between them.
- Not touching, randomly distributed → gas state.
- Only one type of atom → element.

✔ Classification: Gas element

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4)

- Green and yellow spheres paired together as diatomic molecules.
- All molecules are identical (each has one green + one yellow).
- Molecules are not closely packed, some spacing → gas or liquid?
- But since they're not touching and randomly spaced, likely gas.
- Since they’re chemically bonded, this is a compound.

✔ Classification: Gas compound

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5)

- A single molecule: two red spheres joined, with two small gray spheres on outer sides.
- Looks like O₂ with something else? Wait — possibly CO₂? But CO₂ is linear: O=C=O.
- Here: Red–Red, with gray on ends → could be Cl₂O₂ or just a diatomic molecule with attachments?
- But likely two large red atoms and two small gray atoms → perhaps a molecule like O₂ with impurities?
- Actually, if it's just two red atoms bonded, and gray are separate, but shown attached → maybe a compound.
- But it's only one molecule shown, so hard to tell.
- But since it's a single molecule, it might represent a compound molecule.

Wait — actually, this seems like a single molecule of a compound, e.g., CO₂ if red is oxygen, gray is carbon? But that would be C=O=O, not symmetric.

Alternatively, if red = O, gray = H, then H–O–O–H → hydrogen peroxide?

But it’s symmetric, so perhaps O₂ with two H atoms attached? That's H₂O₂ — hydrogen peroxide.

So this is a molecule of a compound.

But since only one molecule is shown, it's not showing a state.

However, in such diagrams, a single molecule often represents the chemical formula of a compound.

✔ Classification: Compound (molecular)

(But note: not a state — just a molecular representation.)

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6)

- One blue sphere alone.
- No bonds, no other particles.
- Could represent an atom of an element.

✔ Classification: Atom of an element

Or more broadly: Element (in isolated form)

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7)

- Blue and white spheres forming small groups.
- Each group has one blue and two white → like water (H₂O).
- All molecules are identical, but spread out, not touching → gas?
- But they are not tightly packed, but still somewhat close? Wait — there's space between molecules.
- But no fixed shape, molecules free to move → gas.
- Or could it be liquid? In liquids, particles are closer.

But here, clear gaps between molecules → gas.

✔ Classification: Gas compound

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8)

- Red and yellow spheres alternating in a tight, regular lattice.
- Two different colors → two different elements.
- Regular structure → solid.
- Since two elements are chemically bonded in a fixed ratio, this is a compound in solid state.

✔ Classification: Solid compound

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✔ Final Classifications:

| Diagram | Classification |
|--------|----------------|
| 1) | Liquid compound |
| 2) | Solid element |
| 3) | Gas element |
| 4) | Gas compound |
| 5) | Compound (molecule) |
| 6) | Element (atom) |
| 7) | Gas compound |
| 8) | Solid compound |

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📌 Summary:

- Elements: 2 (solid), 3 (gas), 6 (atom)
- Compounds: 1, 4, 5, 7, 8
- States:
- Solid: 2, 8
- Liquid: 1
- Gas: 3, 4, 7
- 5 and 6 are single particles/molecules — not showing state

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🧠 Notes:

- Diagram 5 is a molecule, not a bulk sample → so it's not classified by state.
- Diagram 6 is a single atom → not a substance in bulk.

If you're classifying by type of substance (element/compound/mixture), then:
- Elements: 2, 3, 6
- Compounds: 1, 4, 5, 7, 8
- Mixtures: None shown

But if including states, then:

| Diagram | Type | State |
|--------|-------------|-----------|
| 1 | Compound | Liquid |
| 2 | Element | Solid |
| 3 | Element | Gas |
| 4 | Compound | Gas |
| 5 | Compound | N/A (molecule) |
| 6 | Element | N/A (atom) |
| 7 | Compound | Gas |
| 8 | Compound | Solid |

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Let me know if you'd like these grouped into categories like "elements", "compounds", etc.