As we look at our surroundings, we see a large variety of things with different shapes, sizes and textures. Everything in this universe is made up of material which scientists have named ‘matter’. All the things such as stones, clouds, food, stars, plants, even a small drop of water occupy space and have mass. In other words, the matter is something which has mass, occupy volume, can have physical resistance, inertia and can be realized by the sense organs.
Philosophers classified matter in the matter in form of five basic elements- air, earth, fire, sky, and water. According to them, everything, living or non-living was made up of these five basic elements.
Properties of Matter
- Matter is made up of very small particles that are beyond our imagination
- The particles have space in between them, called the intermolecular space
- They are continuously moving i.e, they possess kinetic energy. As the temperature rises, Speed of the particles increases. Due to which the kinetic energy of the particles increases.
- They attract each other. The force of attraction responsible for keeping them together is called intermolecular force.
- The strength of this force of attraction varies from one kind of matter to another.
Particles of Matter
Matter has mainly two particles
The word atom has been derived from Greek word atomos meaning indivisible. AN atom is the smallest particles of an element that may or may not exist independently and retain all its chemical properties i.e., takes part in chemical reactions. Atoms of different elements have different masses and chemical properties.
A molecule is a group of two or more atoms that are chemically bonded together. It can be defined as the smallest particle of an element or a compound that is capable of independent existence and shows all the properties of that substance. However, it does not take part in a chemical reaction.
Types of Molecules
These are of two types
- Homomolecules or Molecules of the Element: These are the molecules of an element constituted by the same type of atoms. e.g., O2, H2, H2, N2 etc. The number of atoms constituting a molecule is called its atomicity. e.g., atomicity of phosphorus (P4) is four and of sulfur (S8) is eight.
- Heteromolecular or molecules of the compounds In these molecules, atoms of different elements join together in definite proportions.
Examples of Heteromolecules
|Compound||Combining Elements||Ratio by Mass|
|Water (H2O)||Hydrogen, Oxygen||1:8|
|Ammonia (NH3)||Nitrogen, hydrogen||14:3|
|Carbon dioxide (CO2)||Carbon, oxygen||3:8|