Understand the Difference Between Atoms and Molecules

Take a look around you now. Can you think of one thing that everything you can see has in common?

Tricky isn't it? Well, there is something that links everything you can see together - everything is made up of the same things - atoms! And in fact everything you can't see is also made of atoms too, like gases in the air. Cool hey?

Atoms are the building blocks of everything. They are super-small, and can't be seen with the naked eye. They have a radius of about 0.1 nanometre.

A bacterium is about 10,000 times bigger than an atom, and we need a microscope to even see them! That's small!

Atoms can exist on their own or be joined to other atoms of the same type to make up an element. They can also form bonds with other atoms to form compounds. 

Because we can't see them, we show atoms as small coloured circles. Atoms of the same element are the same colour and size. Different types of atoms would be shown as different coloured circles. 

The model above shows the atoms in a molecule of ethanol, which is a compound. The circles represent individual atoms. The blue atoms are all hydrogen, so they are all the same colour and size. The red circle is oxygen and the black circles are carbon. So we can see that ethanol is made up of three different types of atom. 

A common compound we may come across is water - we rely on water to keep us alive!

As you can see the red circle is an atom of oxygen, and the white circles are hydrogen atoms. So water is made up of two different types of atom, which is why it has the formula H₂O.

Ready for some questions on these little things we call atoms? Great stuff, let's take a look together........