- Atom and its structure
- Discovery of Electron(Cathode rays)
- Properties of Cathode rays
- More on Properties of Cathode rays
- Discovery of Proton
- Properties of positive rays
- Discovery of Neutron
- Properties of Neutron
- Measurement of e/m Value of Electron
- Measurement of Charge on Electron-Millikan's Drop Method
- More on Measurement of Charge on Electron
- Mass of Electron
- Properties of Fundamenal Particles
- Rutherford's Atomic Model
- Advantages and Defects in Rutherford's Atomic Model

- Bohr's Atomic Theory
- Derivation of Radius of Revolving Electron in nth Orbit
- More on Derivation of Radius of Revolving Electron in nth Orbit
- Energy of Revolving Electron
- More on Energy of Revolving Electron
- Energy of Electron in nth Orbit
- Calculations of Frequency of Photons by Bohr's Theory
- Calculations of Wave Numbers of Photons by Bohr's Theory
- Defects of Bohr's Atomic Model
- More on Defects of Bohr's Atomic Model
- Hydrogen Spectrum
- More on Hydrogen Spectrum
- Calculation of Energy for Lithium ion
- Lyman Series
- Balmer Series
- Paschen Series
- Brackett series
- Pfund series
- Calculation of Wave Number of Spectral series

- Planck's Quantum Theory
- More on Planck's Quantum Theory
- Conversion of Energy to Wavength, Frequency and Wave Number

- Quantum Numbers
- Principal Quantum Numbers (n)
- Azimuthal Quantum Numbers (l)
- Magnetic Quantum Numbers (m)
- Spin Quantum Numbers (s)
- Quantum Numbers of Electrons
- Calculation of Combination of Quantum Numbers
- Shape of s-Orbitals
- Shapes of p-Orbitals
- Shapes of d-Orbitals