Chemistry Chapter 2: Structure of Atom

Introduction:
The chapter "Structure of Atom" deals with the fundamental structure of the atom and its properties.

1. Dalton's Atomic Theory:
Dalton's atomic theory is based on the following postulates:
- All matter is made up of tiny particles called atoms.
- Atoms of the same element are identical in mass and properties.
- Atoms of different elements are different in mass and properties.
- Atoms combine in small whole-number ratios to form compounds.
- Chemical reactions involve the rearrangement of atoms.

2. Discovery of Subatomic Particles:
The discovery of subatomic particles such as electrons, protons, and neutrons led to the development of a new atomic model.
- JJ Thomson discovered the electron using the cathode ray tube.
- Rutherford discovered the nucleus of the atom using the gold foil experiment.
- James Chadwick discovered the neutron.

3. Atomic Number and Mass Number:
The atomic number of an element is the number of protons in the nucleus of an atom. The mass number is the sum of the number of protons and neutrons in the nucleus of an atom.

4. Isotopes:
Isotopes are atoms of the same element with different numbers of neutrons. They have the same atomic number but different mass numbers.

5. Electronic Configuration:
The electronic configuration of an atom describes the arrangement of electrons in its various shells or energy levels. The electronic configuration of an atom determines its chemical properties.

6. Quantum Mechanical Model of Atom:
The quantum mechanical model of the atom describes the behavior of electrons in terms of probabilities. It is based on the principles of wave-particle duality and the uncertainty principle.

Conclusion:
The chapter "Structure of Atom" provides a basic understanding of the fundamental structure of the atom and its properties. It is important for students to have a clear understanding of this chapter as it forms the foundation for further studies in chemistry.