Fundamentals of Atomic Structure and Models

📋 Course Outline

1. Origins of atomic theory
2. Thomson’s plum pudding model
3. Rutherford’s gold foil experiment
4. Bohr’s atomic model
5. Atomic mass and the neutron
6. Atomic number and mass number
7. Electronic configuration and valency
8. Isotopes and their uses

📖 1. Origins of atomic theory

🔑 Key Concepts & Definitions

• Parmanus: Parmanus are smallest, endlessly divisible particles proposed in ancient Indian thought, said to be too small for the senses.
• Atomos: Atomos are indivisible particles proposed by ancient Greek thinkers as the basic constituents of matter.
• Dalton’s atomic theory: Dalton’s atomic theory states that all matter is made of indivisible atoms that act as the fundamental building blocks.

📝 Essential Points

• Ancient Indian thinkers (in the Vaisesika Sutras) proposed parmanus as infinitely small particles that cannot be perceived by the senses.
• Ancient Greek philosophers used atomos as the name for indivisible particles, forming a similar idea to parmanus.
• The word atom began as an imaginary concept rather than something confirmed by experiments.
• In 1808, John Dalton proposed a scientific atomic theory based on experiments available at that time.
• Dalton’s model treated atoms as indivisible particles that cannot be broken into smaller parts. (i)

💡 Memory Hook

Parmanus (India) and atomos (Greece) are “imagination roots,” while Dalton (1808) is “experiment roots” of atomic theory.