Everything we can see and touch, and quite a lot that we can’t as well, is made of tiny particles called atoms. Some substances, like particles of this iron, contain only one kind of atom. Iron is an ...

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 ...

Chemical reactions occur when elements or compounds combine and create new compounds. Elements are substances that contain only one type of atom and are represented by unique symbols on the periodic ...

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 pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a ...