Practise Identifying Atoms and Molecules in Diagrams

Atoms are the building blocks of all matter. Everything is made up of atoms.

Even you are made up of atoms! 

Atoms are the simplest particle of an element. Different things are made of different types of atoms. A piece of gold for example is made up of lots of gold atoms. Oxygen is made up of oxygen atoms. 

We can't see individual atoms with the human eye as they are just so small. Even the most powerful microscopes struggle to see them. Even things like bacteria are much bigger than an atom - they are about 10,000 times bigger in fact!

Atoms have a radius of about 1 nanometre. More than 10 million atoms of hydrogen would be able to fit on a pin head.

Because we can't easily see atoms we can picture atoms as small balls, and when we draw them we often just draw small circles. Each small circle would represent a single atom. 

All atoms of the same type would be drawn as the same size and colour circle - they all need to look exactly the same. Atoms from different elements would be drawn as different colours, and maybe even different sizes. So you can easily determine if a picture of a molecule shows just one type of atom or many.

Let's see a molecule of water below:

You can see that the oxygen atom is red and quite big, and the hydrogen atoms are white and a bit smaller. It shows us that water is made up of two types of atom - oxygen and hydrogen. 

But now let's look at gold:

All of the atoms are identical. The same colour and size. That tells us that gold is made up of only one type of atom. 

Let's find out more by tackling the questions!