The graphite refill used in pencil is made up of element called Carbon. We can break the graphite into smaller and smaller pieces. In fact, if we have an even finer knife, we can break it even smaller. If keep cutting the minuscule graphite into smaller and smaller particle, we will reach a point where we reach smallest constituent of graphite- carbon atom. If we break that carbon atom apart, then it will no longer exhibit the properties of carbon.
The smallest unit of an element that exhibits the properties of the element is called as ‘atom’. All the matter is composed of tiny particles called atom. Water , rice , in short everything we see around is made up of atoms.
An atom is the basic unit of a matter.
Even with the best of optical microscope we cannot see atoms. However there are advanced instruments that help us to image the atoms on the surface of a material.
For example the following figure shows an image of the surface of silicon.
An image of the surface of Silicon
The most abundant type of atom in the universe is thehydrogen atom. Nearly 74%of the atoms in the universe are hydrogen atoms. However on Earth the three most abundant atom are iron, oxygen, and silicon.