Chemistry: What Is Matter? Atoms and Molecules
Exploring the tiny particles that make up everything around us
Chemistry: What Is Matter? Atoms and Molecules
Exploring the tiny particles that make up everything around us
Chemistry - Grade 4-5
- 1
Matter is anything that has mass and takes up space. Name three examples of matter you can find in a classroom.
Look for things you can touch, hold, or see around you.
Examples of matter in a classroom include a desk, a pencil, and a book because each one has mass and takes up space. - 2
Which item is not matter: a rock, air, light, or water? Explain your answer.
Light is not matter because it does not have mass or take up space like a rock, air, or water does. - 3
A balloon is filled with air and gets bigger. How does this show that air is matter?
Think about what happens inside the balloon when more air is added.
The balloon gets bigger because air takes up space. This shows that air is matter because matter has volume and takes up space. - 4
An atom is the smallest basic piece of an element. Use this idea to explain why atoms are sometimes called building blocks of matter.
Atoms are called building blocks of matter because they join together in different ways to make all kinds of materials and objects. - 5
A molecule is made when two or more atoms are joined together. Is a single oxygen atom a molecule? Explain.
Count how many atoms are in the example.
A single oxygen atom is not a molecule because a molecule must have two or more atoms joined together. - 6
Look at a model with one large oxygen atom joined to two smaller hydrogen atoms. What molecule does this model show?
The model shows a water molecule because water is made of one oxygen atom joined to two hydrogen atoms. - 7
The formula for water is H2O. What do the H, the 2, and the O tell you?
In a chemical formula, a small number tells how many atoms of that element are in the molecule.
The H means hydrogen, the 2 means there are two hydrogen atoms, and the O means oxygen. H2O has two hydrogen atoms and one oxygen atom. - 8
Carbon dioxide has the formula CO2. How many carbon atoms and oxygen atoms are in one carbon dioxide molecule?
One carbon dioxide molecule has one carbon atom and two oxygen atoms. - 9
Which has more total atoms in one molecule: H2O or CO2? Explain how you know.
Add the number of atoms shown in each formula.
Both H2O and CO2 have three total atoms in one molecule. H2O has two hydrogen atoms and one oxygen atom, while CO2 has one carbon atom and two oxygen atoms. - 10
Salt is made of tiny particles arranged together. A grain of salt is much too small to see its atoms with your eyes. Why do scientists use models to study atoms and molecules?
Scientists use models because atoms and molecules are too small to see with only our eyes. Models help people understand their shapes, parts, and how they join together. - 11
Sort each example as matter or not matter: steam, sound, juice, and shadow.
Ask whether each thing has mass and takes up space.
Steam and juice are matter because they have mass and take up space. Sound and shadow are not matter because they do not have mass or take up space. - 12
A student says, 'All matter is made of atoms, but not all atoms are joined into molecules.' Is the student correct? Explain.
The student is correct. Matter is made of atoms, and some atoms are joined together to make molecules, but some atoms can exist without being part of a molecule. - 13
A diagram shows three different particle pictures: one single atom, two atoms joined together, and many molecules close together. Which picture represents a molecule?
A molecule must show atoms connected as one particle.
The picture with two atoms joined together represents a molecule because a molecule is made of two or more atoms connected together. - 14
Ice, liquid water, and water vapor are all made of water molecules. What changes when water freezes or boils: the molecules themselves or how the molecules move and spread out?
The substance is still water in all three forms.
The water molecules themselves stay the same. What changes is how the molecules move and how close together or spread out they are. - 15
Write one sentence explaining the difference between an atom and a molecule.
An atom is one tiny building block of matter, while a molecule is made of two or more atoms joined together.