1. particle nature of matter
1.1. matter
1.1.1. it is defined as anything which occupies space and has mass
1.1.2. according to Greek philosophers there were four elements- fire,water,air and earth
1.1.3. according to Indian philosophers there were five elements-sky,air,fire,water and earth
1.1.4. it is made of basic building blocks called elements
1.2. element
1.2.1. there are 118 elements
1.2.2. it is defined as a substance which cannot be subdivided into two or more simpler substances by any chemical means
1.2.3. if the matter is only one kind of element then the smallest unit of that is an atom
1.3. atom
1.3.1. can only be seen under powerful microscopes
1.3.2. it is defined as the smallest unit of an element which may or may not have its own independent existence but always takes part in chemical reaction
1.3.3. if the matter is made of two or more kinds of different elements then the smallest unit of matter is a molecule
1.4. molecule
1.4.1. can only be seen under powerful microscopes
1.4.2. it is defined as the smallest unit of matter which always has its own independent existence and retains complete physical and chemical properties
1.4.3. they are always in continuous motion
1.4.3.1. example
1.4.3.1.1. when a drop of perfume in one corner of a closed room in which there is no motion of air, the fragrance of the perfume will spread around the room
2. kinetic theory of matter
2.1. the molecules are in continuous motion and have kinetic energy
2.2. if the temperature increases the kinetic energy increases and if the temperature decreases then the kinetic energy decreases
2.3. the molecules always attracts each other. the force of attraction between similar kinds of molecules is force of cohesion and the force between different kinds of molecules is force of adhesion
2.4. the empty space between molecules is called intermolecular space
2.5. the force of attraction molecules is called intermolecular force of attraction
2.6. the intermolecular force of attraction increases if the intermolecular space between the molecules decreases
3. arrangement of molecules
3.1. solid
3.1.1. molecules are tightly packed
3.1.2. the force holds the molecules in one place
3.1.3. because of the fixed position of the molecules they have a fixed volume and shape
3.1.4. the intermolecular space is small
3.1.5. they are rigid
3.2. liquid
3.2.1. the molecules are less tightly packed
3.2.2. the intermolecular spaces are large
3.2.3. the molecules change their position
3.2.4. they take the shape of the containing vessel
3.2.4.1. t
3.2.5. they have definite volume