MS-PS1-1: Atoms and Molecules

MS-PS1-1
Atoms and Molecules

Middle School

​

Learning Objectives

• Create models showing how atoms join to make molecules and larger structures.

• Tell the difference between simple molecules and large, extended structures.

• Explain how a substance's properties depend on the type and arrangement of its atoms.

• Describe how atoms in natural resources are rearranged to create new synthetic materials.

Key Vocabulary

​

Atom

The basic unit of a chemical element, representing the smallest particle of that element.

​

Element

A pure substance made up of only one type of atom, defined by its atomic number.

​

Molecule

A group of two or more atoms that are held together by chemical bonds.

​

Compound

A substance that is formed from two or more different elements chemically united in fixed proportions.

​

Extended Structure

A large structure where atoms are linked in a continuous and repeating three-dimensional network.

​

Crystal

A solid material where atoms and molecules are arranged in a highly ordered, repeating pattern.

Key Vocabulary

​

Chemical Formula

A chemical formula is a way to represent the types and numbers of atoms in a substance.

​

Synthetic Material

A synthetic material is a substance made by humans using natural resources through various chemical processes.

​

Natural Resource

A natural resource is any material or substance that is found in nature and can be used by people.

​

Petroleum

Petroleum, also known as crude oil, is a very important natural resource found deep underground.

​

​

Atoms and Elements

• Everything is made of elements, the basic building blocks of all matter.

• There are over 90 different elements, like carbon, oxygen, and gold.

• An atom is the smallest possible unit of any given element.

• Each element is made up of its own unique kind of atom.

​

Multiple Choice

According to the provided information, what are the basic building blocks of all matter?

• Atoms

• Elements

• Matter

• Gold

Multiple Choice

What is the relationship between an atom and an element?

• An atom is the smallest unit of a specific element.

• An element is another name for a group of atoms.

• Atoms and elements are completely unrelated.

• All elements are made from the exact same type of atom.

Multiple Choice

Based on the information, what is the fundamental difference between a single atom of gold and a single atom of carbon?

• The atom of gold is a unique type of atom, while the atom of carbon is a different unique type.

• The atom of gold is a basic building block, but the atom of carbon is not.

• The atom of gold is made of many elements, while the atom of carbon is made of one.

• There is no fundamental difference between an atom of gold and an atom of carbon.

​

​

Forming Simple Molecules

• Atoms can join together to create larger groups called molecules.

• ​These atoms are held together by strong forces called chemical bonds.

• A water molecule (H₂O) has two hydrogen and one oxygen atom.

• A chemical formula like NH₃ shows the atoms in a molecule.

​

Multiple Choice

What is the name for a larger group created when atoms join together?

• A chemical bond

• A molecule

• A chemical formula

• An oxygen atom

Multiple Choice

What is the relationship between the atoms within a water molecule (H₂O)?

• They are held together by chemical bonds.

• They are grouped together by a chemical formula.

• They are separated by empty space.

• They are made of a single type of atom.

Multiple Choice

The chemical formula for ammonia is NH₃. What can you conclude about an ammonia molecule from this formula?

• It is made of one nitrogen atom and three hydrogen atoms.

• It is made of three nitrogen atoms and one hydrogen atom.

• It is made of one nitrogen atom and one hydrogen atom.

• It is made of three atoms of nitrogen and hydrogen combined.

Forming Extended Structures

• Some substances have atoms arranged in a repeating pattern called an extended structure.

• Crystals, like table salt (NaCl), are a common type of extended structure.

• Diamonds are extended structures of carbon atoms, making them extremely hard.

Multiple Choice

What is an extended structure?

• A structure made of atoms in a repeating pattern.

• A structure composed of only a single atom.

• A structure that is always a liquid.

• A structure that is found only in metals.

Multiple Choice

Why are crystals, such as table salt, considered a type of extended structure?

• Because they are both white-colored substances.

• Because their atoms are organized in a repeating pattern.

• Because they can be dissolved in water.

• Because they are both created by humans.

Multiple Choice

The hardness of a diamond is a result of its extended structure of carbon atoms. What conclusion can be drawn from this example?

• The arrangement of atoms in a structure can give a substance its specific properties.

• All extended structures are extremely hard.

• Only structures made from carbon atoms are hard.

• Substances that are hard must be crystals.

How Structure Affects Properties

​

Gases like Helium (He)

• ​Substances like helium are made of individual atoms not attracted to each other.

• ​​Carbon dioxide (CO₂) is made of molecules that are not attracted together.

• ​The atoms or molecules in a gas are spread very far apart.

​

Solids like Salt (NaCl)

• ​Crystalline solids like salt (NaCl) have repeating atoms in extended, ordered structures.

• ​​In materials like sugar or nylon, molecules are attracted to form solids.

• ​This ordered structure gives solids, like salt, their specific and fixed shape.

​

Synthetic Materials

• ​Scientists rearrange atoms from natural resources like petroleum to make new materials.

• ​​This creates synthetic materials like plastic and nylon with very useful properties.

• ​These materials are designed to have specific properties for our everyday use.

Multiple Choice

What is the main factor that determines the properties of a substance, such as its shape and state?

• The way its atoms or molecules are arranged and attracted to each other.

• The type of natural resource it comes from, like petroleum.

• The number of individual atoms in a single molecule.

• The temperature and pressure of its environment.

Multiple Choice

What is the primary difference in the structure of a gas, like helium, compared to a crystalline solid, like salt?

• The particles in a gas are far apart and not attracted, while the particles in a solid are ordered and attracted together.

• Gases are made of individual atoms, while solids are always made of molecules.

• The particles in a gas are made from natural resources, while the particles in a solid are synthetic.

• Solids have a repeating structure, while gases have no structure at all.

Multiple Choice

A scientist wants to design a new synthetic material that is strong and has a fixed shape. How would they most likely achieve this?

• By rearranging atoms to create an ordered structure where molecules are strongly attracted.

• By making sure the atoms are individual and not attracted to each other.

• By using atoms only from natural resources like petroleum without changing them.

• By mixing together different types of gases, like helium and carbon dioxide.

​

Common Misconceptions

Misconception	Correction
All compounds are made of separate molecules.	Some compounds like salt (NaCl) form extended structures, not separate molecules.
Synthetic materials are completely artificial and have no connection to nature.	All synthetic materials are created from natural resources.
If you can't see atoms, they aren't there.	Atoms are the building blocks of matter, but are too small to see.
All man-made materials are bad.	Many synthetics offer benefits like safety, strength, and health.

​

Summary

• All matter is made of atoms, the basic building blocks of elements.

• Atoms can form molecules like H₂O or extended structures like NaCl.

• A substance's properties are determined by the arrangement of its atoms.

• Synthetic materials are made by rearranging atoms from natural resources.

Poll

On a scale of 1-4, how confident are you about describing the atomic composition of substances?

• 1

• 2

• 3

• 4