#### The Periodic Table

The universe is made of atoms. There are around 100 or so atoms that make up the universe as we know it. We have organised the different atoms into a library we call the periodic table. You need to know a little bit about its organisation.

• Identify groups and periods on the periodic table
• Name the major groups/blocks of the periodic table

#### Parts of the Table are Named!

Take a look at the periodic table below, you'll notice that this one's pretty colourful. Each colour represents a different named region of the periodic table. You're expected to know the names of some of these regions. The big yellow blob in the centre contains many of the metals we use in everyday life - these elements are known as the transition metals and the whole region is sometimes called the transition block. The light blue region is called the Alkali Metals, the vivid green region the Halogens and the pink region the Noble Gases. Note that the halogens are still part of the non-metals, they're singled out because you will study them in detail. The other groups/blocks have names but you don't need to know them.

#### Groups and Periods

The Periodic table is organised into groups and periods. Groups are what we normally call columns in everyday life, so for example group 6 consists of oxygen, sulfur, selenium, tellurium and polonium. Periods are, in every other table on the planet, called rows - so period 2 consists of lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine and neon. A common mistake in exams is to forget period 1, hydrogen and helium, because the period starts half-way across the periodic table. Never use the words row and column in an exam, you must use the words group and period or you may be penalised depending on that year's markscheme.

#### Metals and Non-metals

One of the simplest ways of dividing the periodic table is into metals and non-metals. Metals and non-metals have different chemical properties. The diagram on the right shows how the table is divided. The metals are formed from groups 1,2 and the transition metals - this is the yellow shaded area.. The green area forms the non-metals. Except for aluminium the orange area isn't covered at GCSE - it's properties change from metallic to non-metallic as you go to the right of the Periodic Table.