Structure of Atom class 11 notes
Chapter 2. Structure of Atom Some Important Points and Terms of the Chapter 1. The word 'atom' has been derived from the Greek word a-tomio ' which means 'uncutable 'or non-divisible' 2. J.J.Thomson , in 1898 , proposed that an atom possesses a spherical shape (radius approximately 1 0-10 m) in which the positive charge is uniformly distributed. The electrons are embedded into it in such a manner as to give the most stable electrostatic arrangement (Fig. 2.4, NCERT Page 5) Many different names are given to this model, for example, plum pudding, raisin pudding or watermelon. 3. Rutherford's Nuclear Model of Atom : a) Most of the space in the atom is empty as most of the alpha particles passed through the foil undeflected b) A few positively charged alpha particles were deflected. The deflection must be due to enormous repulsive force showing that the positive charge of the atom is not spread throughout the atom as Thomson had pres...