If your Web browser were Java enabled, the clock you see would be running and showing your current time. All materials, whether solid, liquid or gas, are made of atoms.
Atoms are the smallest bits of matter.
Scientists have found over 100 different kinds of atoms. The many different materials we encounter are made from combinations of these atoms. A material in which all atoms are the same kind is called an element. Therefore, there are over 100 different elements. Each element has been assigned a number, called its atomic number.