Notes from Toppers

Atomic Models

1. John Dalton’s Atomic Theory:

  • Indivisibility of atoms.
  • Relative weights of atoms.
  • Law of multiple proportions.

References:

  • NCERT Chemistry Class 11 (Part I), Chapter 1: Some Basic Concepts of Chemistry.

2. Cathode Rays and Discovery of Electrons:

  • Experiments by William Crookes.
  • Discovery of electrons by J.J. Thomson.
  • Properties and characteristics of cathode rays.

References:

  • NCERT Physics Class 12 (Volume I), Chapter 2: Electrostatic Potential and Capacitance.

3. Positive Rays and Identification of Protons:

  • Experiments related to positive rays by Eugen Goldstein.
  • Identification of protons.
  • Properties and characteristics of positive rays.

References:

  • NCERT Physics Class 12 (Volume I), Chapter 15: Nuclei.

4. Rutherford’s Gold Foil Experiment:

  • Experimental setup and observations.
  • Discovery of the atomic nucleus.
  • Rutherford’s model of the atom.

References:

  • NCERT Physics Class 12 (Volume I), Chapter 15: Nuclei.

5. Rutherford’s Model of the Atom:

  • Key features of the nuclear model.
  • Central nucleus with protons.
  • Mostly empty space in the atom.

References:

  • NCERT Physics Class 12 (Volume I), Chapter 15: Nuclei.

6. Nuclear Size and Scattering Experiments:

  • Determination of nuclear size.
  • Scattering experiments and results.
  • Calculation of nuclear radius.

References:

  • NCERT Physics Class 12 (Volume I), Chapter 15: Nuclei.

7. Bohr’s Model of the Atom:

  • Introduction of quantized energy levels.
  • Electron orbits and energy states.
  • Limitations of Bohr’s model.

References:

  • NCERT Physics Class 12 (Volume I), Chapter 15: Nuclei.

8. Quantum Mechanical Model of the Atom:

  • Limitations of Bohr’s model.
  • Development of quantum mechanics.
  • Wave-particle duality and uncertainty principle.

References:

  • NCERT Chemistry Class 12 (Part I), Chapter 2: Structure of the Atom.

9. Quantum Numbers:

  • Four quantum numbers (n, l, ml, and ms).
  • Significance in describing electron properties.
  • Quantum number values and their implications.

References:

  • NCERT Chemistry Class 12 (Part I), Chapter 2: Structure of the Atom.

10. Electron Configurations:

  • Aufbau principle and Hund’s rule.
  • Arrangement of electrons in orbitals.
  • Electron configurations of elements.

References:

  • NCERT Chemistry Class 12 (Part I), Chapter 2: Structure of the Atom.

11. Periodic Trends:

  • Trends in atomic radii.
  • Trends in ionization energies.
  • Trends in electronegativity.
  • Trends in electron affinity.

References:

  • NCERT Chemistry Class 11 (Part I), Chapter 3: Classification of Elements and Periodicity in Properties.


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