Atom-Definition-History of atom-subatomic particles-evidence of atom class 11 chemistry

in this we will Discuss about the basic concept of atom and definition. we also talk about history and subatomic particles of atom.

1. CLASS 11 th – CHEMISTRY- CHAPTER # 01- BASIC CONCEPT Content Concept of Atom History ……Democritus ……John Dalton Definition Subatomic particles Evidence of Atoms …… By simple Microscope ……By Electron Microscope ……By X-ray work

2. CLASS 11 th – CHEMISTRY- CHAPTER # 01- BASIC CONCEPT Concept of atoms : History Democritus:- The concept of atom was given by Greek philosopher Democritus. All matter is composed of simple, indivisible particles Matter could be divided into smaller and smaller particles to reach a basic unit which could not be further subdivided. He called these particles “Atomos”.

3. CLASS 11 th – CHEMISTRY- CHAPTER # 01- BASIC CONCEPT Concept of atoms: History John Dalton Atomic Theory:- All matter composed of atoms. All atoms of same element are identical. Matter is composed of atoms of different elements having different properties. Law of conservation of mass & law of definite proportion could be explained.

4. CLASS 11 th – CHEMISTRY- CHAPTER # 01- BASIC CONCEPT Concept of atoms : History John Dalton Atomic Theory:- Law of conservation of mass:- Matter can not be created or destroyed Law of Definite Proportion :- when atoms combine to form molecules the ratio of atoms is constant.

5. CLASS 11 th – CHEMISTRY- CHAPTER # 01- BASIC CONCEPT Concept of atoms : History J. Berzelius:- He determined atomic mass of elements. He also developed the system of give element a symbol.

6. CLASS 11 th – CHEMISTRY- CHAPTER # 01- BASIC CONCEPT Definition:- Atom is smallest particle of an element which can take part in a chemical reaction.

7. CLASS 11 th – CHEMISTRY- CHAPTER # 01- BASIC CONCEPT Subatomic particles:-

8. CLASS 11 th – CHEMISTRY- CHAPTER # 01- BASIC CONCEPT Evidence of Atoms :- It is not actually possible to see the atoms but the nearest possibility to its direct evidence is by using an electron microscope. Ordinary Optical Microscope : It uses the beam of visible light. Measure the size of object up to or above 500 nm ( 1nm= 10 -9 ). Electron Microscope :- It uses beam of electron instead of visible light.