What is Atom ?
What is Atom ? Definition :- Atom is the smallest indivisible particle of the matter. Atom is made of electron, proton and neutrons. P ARTICLE ELE CTRON P ROTON NEUTRON Discovery Sir. J. J. Thomson (1869) Gold stein (1886) Chadwick (1932) Nature of charge Negative Positive Neutral Amount of charge 1.6 x 10 -19 Coloumb 1.6 x 10 -19 Coloumb 0 M ass 9.11 x 10 -31 kg 1.672614 x 10 -27 kg 1.67492 x10 -27 kg Electrons were discovered using cathode ray discharge tube experiment.Nucleus was discovered by Rutherford in 1911. Cathode ray discharge tube experiment:- A cathode ray discharge tube made of glass is taken with two electrodes. At very low pressure and high voltage,current starts flowing through a stream of particles moving in the tube from cathode to anode. These rays were called cathode rays. When a perforated anode was taken, the cathode rays struck the other end of the glass tube at the fluor