Shaillee Kaushal is teaching live on Unacademy Plus
C-02 STRUCTURE OF ATOM PROTON NUCLEUS NEUTRON Nucleus Proton El ELECTRON This is an important Unit for NEET Neutrons Air at verY low pressure Discharge Tube An ode Cathode rays To Vacuum Pum Voltage Generator
An Indian philosopher Maharishi Kanad postulated that if we go on dividing matter (padarth) we shall ultimately get the smallest particle beyond which further division will not be possible. These smallest particles were named parmanu. Democritus and Leucippus also suggested that if we keep on dividing matter a stage will come when particles obtained cannot be divided further. These particles were called atoms - John Dalton for the first time explained the atom by putting forward this theory the atomic theory. According to this theory atom is the smallest indivisible particle which participates in a chemical reaction. In 1833 Michael Faraday showed that there is a relationship between matter and electricity. This for the first time suggested that atom is not the smallest indivisible particle of all matter but was made up of smaller particles. The foundation of modern picture of atom was laid by J.J Thomson and Ernest Rutherford. The atom consists of several particle called subatomic particles like electron, proton, neutron, positron, neutrino, meson etc. Out of these the electron, the proton and the neutron are called fundamental particles.
Characterstics of Cathode rays: 1. They travel in straight lines away from the cathode with very Cathode Rays-Discovery of electron. high velocities. From 109 -1011 cm per second. A shadow of metallic object placed in the path of cathode rays is casted on th wall opposite to the cathode. 2. They produce heat energy when they collide with metter this can be shown by placing aluminum foil in the path of cathode rays. 3. When the rays are passed between two electrically charged plates, they are deflected towards the positively charged plate. This shows that the cathode rays are negatively charged. 4. Cathode rays are mechanical in nature. This can be proved by placing a spinning wheel in the path of cathode rays. The wheel starts to move. This shows that cathode rays have kinetic energy Thus cathode rays consist of material particles which have mass and velocity Cathode H TO vacuum Cathode rays To vacuum FluorescentGlowing glass These netgatively charged particles were called negatrons by J.J Thomson and latter electron by stoney Cathode rays produce X-rays. They effect the photographic plate To vacuum The nature of cathode rays are independent of the nature of the cathode the gas in the discharge tube.
Chemistry BY Shaillee Kaushal You tuber Mentor in Chemistry Teaching experience of 14 years