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All the different elements are arranged in the periodic table.

Here are the main features of the table:

• the horizontal rows are called periods
• the vertical columns are called groups
• elements in the same group are similar to each other
• the metals are on the left and the non-metals are on the right
• the main groups are numbered from 1 to 7 going from left to right, and the last group on the right is Group 0
• the block in between Group 2 and Group 3 is where the transition metals are placed
• there are only two elements in Period 1 (hydrogen and helium)

The zig-zag line in this diagram separates the metals, on the left, from the non-metals, on the right. Hydrogen is a non-metal but it is often put in the middle.

Most elements are metals, rather than non-metals.

Each element has its own chemical symbol, made from letters. Only elements are found in the periodic table, never compounds. For example, substances like water and copper sulfate are not in the periodic table because they are compounds.