There are lots of different substances but only just over a hundred elements. An element is a substance that is made up of only one kind of atom. The atoms in a particular element are the same as each ...

There are different ways to separate mixtures, for example by filtration, crystallisation, distillation, or chromatography. The method chosen depends upon the type of mixture. The periodic table - OCR ...

The periodic table of the elements, principally created by the Russian chemist, Dmitry Mendeleev (1834-1907), celebrated its 150th anniversary last year. It would be hard to overstate its importance ...