Page 11 - The Periodic Table Book
P. 11

Elemental                                                      Ancient ideas


                                                                The idea of elements is very old, dating
                                                                back about 2,600 years to ancient Greece.
                                                                However, Greek thinkers believed that
                                                                the world was made of just four elements:
                                                                earth, water, fire, and air. Empedocles, an
 building blocks     Earth                     Water            that these elements made up all structures.          Introduction
                                                                influential scholar, was the first to propose

                                                                Only much later did scientists learn that
                                                                none of these are actually elements. For
                                                                thousands of years, everybody from ancient
                                                                Egyptian priests to medieval European
                                                                alchemists, speculated about the definiton
                                                                and classification of an element.



                      Air                      Fire
           Elements in and around us
           About 99 per cent of the human body is made from just
           six elements, though they are combined together to form
           thousands of different compounds. On the other hand,
           Earth’s atmosphere is a mixture of gases, most of which
           are pure elements. About 99 per cent of the air is made
           from nitrogen and oxygen.
                                             Others 0.1%
           Phosphorus 1%  Others 1%
                                                    Argon 0.9%
         Calcium 1.5%
                           Nitrogen 3%
                           Hydrogen 10%             Oxygen 21%


                               Carbon                                       Iranian alchemists in their workshop
                               18.5%
                                                                Alchemy and mysticism
                                                                Chemists are scientists who study elements and compounds.
                                                                However, before they existed, the alchemists were medieval
                               Oxygen               Nitrogen    researchers. Believing in a mixture of science and magic,
                               65%                  78%         alchemists tried to change ordinary metals (such as lead)
                                                                into gold. They failed because elements cannot be changed
                                                                from one type to another. But, in the process, they discovered
                                                                many new elements and developed several processes that
                                                                chemists still use today.

                   Human body          Earth’s atmosphere
                                                                    ROBERT BOYLE


                                                                  The first person to use
                                                                  science to understand
                                                                  the elements was the
                                                                  Irish scientist and inventor
                                                                  Robert Boyle. He pursued
                                                                  science through reason,
                                                                  and in the 1660s he
                                                                  performed the first
                                                                  chemistry experiments
                                                                  to show that much of
                                                                  what the alchemists
                                                                  believed was wrong.



 Bismuth crystals                    Gold crystals                                                                     9





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