Atoms and Molecules

Atoms and Molecules for Class 5 Science

Atoms are the structural and functional unit of matter and a group of atoms is called molecules. Through this concept, the students will be introduced to atoms and molecules and their patterns of organisation in different state matters.

After reading the concept, students will be able to:

Explain the difference between atom and molecule.
Understand different properties of matter.
Summarise the physical properties of matter.
Understand what is density in chemistry.
Analyse the difference between soluble and insoluble substances.

Each concept is explained to class 5 students using descriptions, illustrations, and concept maps. After you go through a concept, assess your learning by solving the two printable worksheets given at the end of the page.

Download the worksheets and check your answers with the worksheet solutions for the concept of Atoms and Molecules provided in PDF format.

Materials:

All things we see around us are made of different materials.
A substance of which a thing is made called a material.

Example:Wood, plastic, rubber, fabrics etc.

Materials vary in the manner they are used.
Every material is made up of matter.

Matter:

Matter is anything that occupies space and has weight.
Matter can be classified into three states—solids, liquids and gases.
Matter can be further subdivided into tiny units that are not visible to the naked eye called molecules and atoms.
Atoms combine to form molecules.

Atoms:

Atoms are the structural and functional unit of matter.
They are called the building blocks of matter and combine to form molecules.
There are 117 kinds of atoms known.

Molecules:

A group of two or more atoms is called a molecule.
A molecule may be formed of similar or different atoms. Molecules of different atoms combine to form compounds.
There is a force of attraction between the molecules which varies in different states of matter.
Both atoms and molecules are too small to be visible through naked eyes.

Physical Properties of Matter:

The properties or characteristics that we can observe with our senses are called physical properties.
Physical properties help us to differentiate one material from the other.

How to Differentiate the Physical Properties of Matter?

Look: By looking at an object, we get an idea about its size, shape, and colour.

Examples:By looking, we can say that an apple is round and red whereas a chilli is green and long.

Feel: By feeling an object, we can analyse whether it is smooth, soft, hard or rough.

Examples:Cotton feels soft, whereas a rock feels hard.

Smell: Every material has a unique smell that help us distinguish them.

Examples:Cotton feels soft, whereas a rock feels hard.

Taste: We can also identify certain things by their tastes. However, one cannot taste all types of things.

Examples:A chocolate tastes sweet, whereas a lemon tastes sour.

Density: The density of an object varies. It depends on the type of material used to make that object.

Examples:A plastic ball of the same size as a wooden ball will be less dense.

Solubility: Solubility varies from substance to substance. Some substances completely dissolve in the solvent, whereas some do not dissolve instead they settle at the bottom.

Examples:Salt and sugar are soluble in water, whereas chalk powder and sand are insoluble.

New Words:

Density:It is the ratio of mass and volume of an object. Mass is defined as the amount of matter present in an object. Volume is defined as the amount of space occupied by an object.

Solubility: It is the ability of a substance to dissolve in a solvent.

Solvent: A solvent is usually a liquid in which other materials dissolve. Water is the most commonly used solvent.

Did You Know?

Atoms are the smallest unit of matter. They are further divided into subatomic particles—protons, neutrons and electrons.
The most commonly found atom in the universe is the hydrogen atom.