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 ...

A chemical compound is a chemical substance consisting of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. The ratio of each element is ...

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