The Periodic Table
What is it?
The periodic table is the chemist's friend. It lists all of the approximately 100 elements which all materials are made of.
Above is an example of the periodic table. It looks quite scary but there is no reason to learn it: it is on the wall of every science classroom and in the back of every chemistry textbook. But once you know how to read it, chemistry starts to get a lot easier.
How does it work
The table is arranged into groups (columns) by the number of electrons in the outer electron field. So Na in grp. I has only 1 outer electron, whereas Cl in grp. VII has 7. From left to right are periods of increasing atomic number.
The groups are very important for understanding how any element will behave. The elements in each group share similar characteristics because they have the same number of outer electrons, so react similarly. Despite this, the reaction rate varies as you go down the periods because the distance between the outside electrons and the atom nucleus gets greater.
If you still don't understand atomic structure, then see [scienceaid.co.uk/chemistry/basics/theatom.html].