Particles of Matter

Atom

Atoms are primarily made up of three main particles: Proton, Neutron and Electron. Protons and Neutrons are found in the Nucleus and Electrons revolve around in their orbits around the Nucleus. Neutrons have no charge, whereas Protons are positively charged and Electrons are negatively charged. The number of Protons and Electrons in an atom are always the same. As they are of opposite charges, they attract each other. This is why an Electron stays in its orbit around the Nucleus.

Element

An Element is made up of atoms with identical number of protons in each of its nucleii. Elements cannot be further broken to form a simpler substance by normal chemical means. Our environment, such as air and water, constitutes of many such elements. For example, the Oxygen that we breathe is an element. Pure Iron or Copper are also elements. They fall under the metal group.

Molecules of Oxygen and Hydrogen participating in a reaction to make water

Molecule

A group of two or more atoms composed together defining the chemical or physical state of a substance (for example solid, liquid or gas) is called a Molecule. These are the smallest part of a compound that can participate in a reaction to create a change in the physical and chemical property of the very substance. For example: molecules of Oxygen and molecules of Hydrogen participate in a particular reaction and water is formed.

Compound

Let us take the same example of Oxygen and Hydrogen. Oxygen and Hydrogen both are gases. When combined together under certain circumstances they become water, which is a liquid. Water is a compound. Hence a compound is the unification of 2 or more elements through a reaction. A compound might have an absolute different physical and chemical property than that of the elements that are used to create it.