Everything that occupies space and has mass is called matter. Matter is composed of tiny particles, which cannot be seen with the naked eye, called atoms. This chapter deals with atoms, molecules, elements, compounds, chemical formulae and atomicity, and the effect of temperature on solids, liquids and gases.
1. Atoms
- Graphite lead used in pencils is made up of the element carbon. If we keep cutting graphite into smaller and smaller particles, we reach its smallest constituent – the carbon atom.
- Atom: the smallest unit of an element that exhibits the properties of that element.
- All matter is composed of atoms; water, rice and everything we see around is made up of atoms. An atom is the basic unit of matter.
- Even with the best optical microscope we cannot see atoms; advanced instruments help us imagine atoms on the surface of a material (e.g. the surface of silicon).