For GCSE Chemistry it is vital that students have a good understanding of the periodic table. In this quiz we take a look at how the periodic table is organised into groups and periods, and also at some of the information we can get about elements from their position in the table.
The ancient Greek philosophers knew very little about science, however, that didn't stop them coming up with ideas to help to explain the world around them. They believed that everything was made from four elements - fire, air, earth and water. It's a long way from our current model of over 100 elements arranged into 8 groups but there are some people who stiill believe this mystical idea! It took 1,000 years before the alchemists of Islam started to carry out experiments systematically. They managed to discover some of the materials that made up the world around them, however, since they were actually looking for a mythical substance that would turn base metals into gold (the Philosopher's Stone), they never actually thought of devising a periodic table. It would have been a very difficult task anyway because some of the substances they discovered were compounds; only a few of them were what we now know are true elements.
In the middle of the seventeenth century, Irish scientist Robert Boyle came up with a definition of an element that lasted until the the discovery of sub-atomic particles, he said that "an element is a substance that could not be broken down into a simpler substance by a chemical reaction". Twenty years after this, French scientist Antoine de Lavoisier wrote what is regarded as the first chemistry textbook. In it, he began the search to classify the elements in a meaningful way. His list of elements contained substances such as oxygen, nitrogen, mercury and zinc but there were also some compounds that he believed to be elements, plus light and heat, which at the time were still believed to be materials rather than forms of energy. His contribution to the periodic table was to classify his list of elements as metals and non metals. Unfortunately, Lavoisier was a nobleman and as a result, during the French Revolution, he was murdered by the revolutionaries - he was guillotined in Paris.
In the 1800s, chemists were regularly finding new elements and they desperately needed a way to organise them to see the patterns that were becoming evident. Many scientists made attempts at this, including a teacher called John Dalton and a French chemist called Alexandre-Emile Beguyer de Chancourtois (what a name!!). A Russian scientist named Dmitri Mendeleev placed the elements in order of atomic mass whereas we now use atomic number, which was unknown at the time. For the story of the periodic table, you need to go to the next quiz ... but hopefully not before you have tried this one and tested your knowledge of how the elements are arranged into the groups of the periodic table!