Classifying Matter Using Particle Models 1 | Worksheet - Free Printable

Here are the answers to the questions on your worksheet, based on the particle models provided.

1. Check the boxes to indicate whether each model has atoms, molecules, elements, and/or compounds.

To solve this, we look at the key:
* Atom: A single circle (yellow or teal).
* Molecule: Two or more circles bonded together.
* Element: Only one type of atom (all circles are the same color).
* Compound: Different types of atoms bonded together (different colors in one group).

Model A:
* Contains separate yellow circles (Atoms) and pairs of yellow circles (Molecules).
* Since everything is yellow, it is an Element.
* It does not have different colors bonded, so it is not a Compound.
* Check: Atom, Molecule, Element.

Model B:
* Contains pairs of teal circles bonded together (Molecules).
* Since everything is teal, it is an Element.
* Check: Molecule, Element.

Model C:
* Contains pairs of yellow circles bonded together (Molecules).
* Since everything is yellow, it is an Element.
* Check: Molecule, Element.

Model D:
* Contains separate yellow circles and separate teal circles (Atoms).
* They are not bonded, so there are no Molecules or Compounds.
* Because there are two different types of atoms mixed but not bonded, the whole mixture is not a pure Element, nor is it a Compound. However, the individual particles *are* atoms of elements. Usually, in these charts, if it's a mixture of uncombined elements, you check "Atom". You generally do not check "Element" for the whole box because it's a mixture, but the components are elemental atoms. Let's look closer. The question asks if the *model* has these things. Model D has atoms. It does not have molecules. It does not have compounds. Does it have "Elements"? It contains elemental substances, but they are mixed. Typically, "Element" implies a pure substance. Let's stick to the particles present. It definitely has Atoms.
* *Correction/Refinement:* In many middle-school contexts, a box with mixed unbonded atoms is just classified as having "Atoms". It is a mixture of two elements. Let's look at Model E and F for comparison.
* Check: Atom.

Model E:
* Contains groups of 3 atoms bonded together (2 yellow, 1 teal). These are Molecules.
* Because they have different colors bonded, they are Compounds.
* Check: Molecule, Compound.

Model F:
* Contains some pairs of yellow circles (Molecules, which are Elements).
* Contains some groups of 3 atoms (2 yellow, 1 teal) (Molecules, which are Compounds).
* So it has Molecules, Elements (the yellow pairs), and Compounds (the mixed groups).
* Check: Molecule, Element, Compound.

Summary Table for Question 1:

| | A | B | C | D | E | F |
| :--- | :---: | :---: | :---: | :---: | :---: | :---: |
| Atom | ✓ | | | ✓ | | |
| Molecule | ✓ | ✓ | ✓ | | ✓ | ✓ |
| Element | ✓ | ✓ | ✓ | | | ✓ |
| Compound| | | | | ✓ | ✓ |

*(Note on Model D: While it contains elemental atoms, it represents a mixture. If your teacher considers "Element" to mean a pure substance, you would not check it for D. If they mean "contains elemental particles," you might. Based on standard keys, usually only pure substances get the "Element" or "Compound" label for the whole box. Model D is a mixture of elements. I have left Element unchecked for D above, as it is not a pure element.)*

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2. Which models have molecules? Support your answer with details from the models.

Answer:
Models A, B, C, E, and F have molecules.

Supporting Details:
* According to the key, a molecule is formed when atoms are joined by chemical bonds. In the diagrams, this looks like circles touching or connected by lines.
* Model A has pairs of yellow atoms bonded together.
* Models B and C show only bonded pairs of atoms.
* Model E shows groups of three atoms bonded together.
* Model F shows both bonded pairs and bonded groups of three.
* (Model D does not have molecules because all the atoms are separate and not touching/bonded).

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3. Can an element be made of molecules? Support your answer with details from the models.

Answer:
Yes, an element can be made of molecules.

Supporting Details:
* An element is defined as matter made of only one type of atom.
* A molecule is two or more atoms bonded together.
* If you bond atoms of the *same* type together, you create a molecule that is still an element.
* Model B and Model C prove this. They contain molecules (bonded pairs), but every atom is the same color (teal or yellow). This means they are molecules, but they are also elements because there is only one type of atom present.