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Rutherford’s Experiment and the Nuclear Atomic Model Rutherford’s Experiment and the Nuclear Atomic Model : In 1911, Ernest Rutherford bombarded a thin screen i.e. foil of gold (100 nanometer or 10-7 meter thick) encoated with zinc sulphide, with alpha particles (Helium nuclei). The following observations were made by this experiment : Most of the particles…
Thomson’s Atomic Model Thomson’s Atomic Model : After the confirmation of the presence of electron and proton in the atom, Thomson in 1898 said that the atom is a positively charged sphere in which are embedded the negatively charged electrons. He compared it with the dessert “Plum pudding” in which dry fruits are present scattered…
Properties of the Positive rays Discovery of Proton : In 1886, E. Goldstein used perforated cathode in the immersion tube and observed new type of rays at low pressure and high voltage, which were termed as positive rays. They are also known as the anode rays. Properties of the Positive rays : Positive rays move…
Discovery of Proton Discovery of Proton : In 1886, E. Goldstein used perforated cathode in the immersion tube and observed new type of rays at low pressure and high voltage, which were termed as positive rays. They are also known as the anode rays. Properties of the Positive rays : Positive rays move in a…
Properties of Cathode rays Discovery of electron : J.J. Thomson created high vacuum in immersion tube and applied high voltage on the metal electrode. He observed that green fluorescence is generated on the walls of the tube. With the help of his experiments, Thomson confirmed that on applying high voltage in vacuum there is flow…
Discovery of electron Discovery of electron : J.J. Thomson created high vacuum in immersion tube and applied high voltage on the metal electrode. He observed that green fluorescence is generated on the walls of the tube. With the help of his experiments, Thomson confirmed that on applying high voltage in vacuum there is flow of…
Physical particles of atom and their discovery 1 Electric immersion tube : There is a long glass tube having metal electrode on both ends. A vacuum pump is connected to it, with the help of which the pressure in the tube can be increased or decreased. Even vacuum can be created in the tube with…
What is Atomic Structure ? Since ancient times man has been inquisitive about the change of form of matter, for example when salt is added to water it becomes invisible but its taste is there in the water. On being burnt coal converts into ash. Matter can be grounded to form fine powder. The invisibility…
Purification of Matter or Organic Compounds Purification of Matter : In nature majority of the matter is present in impure form. Hence their purification is essential. There are different methods of purifying different substances. 1. Filtration : Filtration is a method to separate solid from liquid in a heterogenous mixture. In filtration the solid matter…
Changing States of Matter and its Effect Changing States of Matter and its Effect : Whenever there is a change in the state of matter, primarily, the distance between its particles, the energy of its particles and the position of the particles change. 1 Effect of Temperature : On being heated the kinetic energy of…