WHAT ARE MOLECULES?
Molecules are the smallest particle of any substance, which has all the properties of that particular substance. Molecule if broken down further than properties of that substance are lost.
Let us understand by an example. We all know sugar taste sweet. If you break single crystal of sugar into two pieces and taste them one by one, you will find both of them taste sweet. If somehow you are able to break this crystal billion of times to get the smallest particle, even then that particle will tastes sweet. However, if you break this smallest particle further than new particles formed will not taste sweet anymore. Thus, the smallest particle of sugar, which still tastes sweet, is a molecule of sugar.
As molecules are the smallest particle of any substance so, can we call them as the building block of that substance? The answer is NO because we can break molecule further into smaller particles known as atoms. Atoms are basic building blocks of all things around us. Please note we had already discussed atoms in another post – What is an Atom?
There are 118 different kinds of atoms. Most of these atoms do not like to stay alone. Therefore, they combine with other atoms to form bigger size particles known as molecules.
Molecules may consist of –
- same kind of two or more atoms, or
- different kinds of two or more atoms
Difference between Atoms & Molecules
Atoms combine together to make molecules, which in turn make various types of substances around us. Different kinds of atoms combine with each other in varying ratio to form a large variety of molecules and substances. The interesting fact to know here is that there are still many substances, which are still unknown to humanity.
Some difference between atoms and molecules are as below:
- Atoms are basic building blocks.
- There are only 118 different kinds of atoms.
- As most of the atoms do not like to stay alone, thus it is difficult to find a single free atom in nature, except that of inert elements.
- Molecules are bigger size particle consisting of two or more atoms of a same or different kind.
- As atoms combine with each other in varying ratio thus, practically uncountable numbers of molecules are there.
Importance of Molecule
Study of molecules is important because properties of substance or material depend upon molecules it consists of. Molecules together make substance, just as if bricks make a wall. As strength and color of the wall will depend upon kind of bricks used to build it, similarly properties of substance will depend upon kind of molecules used to make it.
Let us take an example, which will clarify things further. When two atoms of hydrogen (H) join, it from a molecule of hydrogen gas (H2) however, when two atoms of hydrogen (H) and one atom of oxygen (O) join, it makes a molecule of water (H2O) which is liquid. Both the substance formed had varying properties –
- H2 (hydrogen gas) is a gas under normal condition.
- Hydrogen gas is flammable and when ignited it burns with a pop sound.
- H2O (water) is liquid under normal condition.
- Another way round we use water to extinguish or control fire.