I. Matter
Everything in the world is made of matter. Matter is composed mainly of particles which are so small that they cannot be seen even with a very powerful microscope.

II.Elements and Atoms
All matter is made of elements, such as oxygen, nitrogen and iron.  All the elements so far discovered by the world have been placed on the periodic table. An atom is the smallest part of an element that still holds the qualities of that element. Atoms are created of even smaller particles called electrons, protons and neutrons.

III. Compounds
Atoms can be bound chemically into a substance called a compound. Compounds are formed when two or more atoms are held together by a force.
Compounds do not have the same qualities as the elements that they were formed with. For example, sodium chloride, also known as table salt is formed by sodium, a metal which is poisonous to consume and by chlorine, a green-yellow gas which is poisonous to breathe. Yet, together they form sodium chloride which we put in our food to give it a salty taste.