AP CHEMISTRY

AP CHEMISTRY

STRUCTURE OF ATOM

HISTORY OF ATOMIC CHEMISTRY

1. Greek Philosopher, Leucipuus and his student Demucritus, gave the term 'Atomos'.

HISTORY OF THE ATOMIC THEORY

• Antoine Lavoisier proposed the law of conservation of mass

• John Dalton said that elements exists as discrete packets of indivisible matter.

Discovery of sub-atomic particles

• Eugen Goldstein first used the cathode rays

• Discovered the positive (canal) rays.

Thompson's Ray Experiment

• J.J. Thompson determined the mass of the cathode rays

• Concluded that cathode rays indeed were small masses

• Called them "corpuscles"

• Gave the "Plum-pudding model"

Rutherford's Experiment

• Did the famous Gold foil experiment

• Discovered the nucleus

• Nucleus had all the positive charge

Bohr's Atomic Model

• Analyzed the Gold foil Experiment

• Gave the planetary model for the arrangement of electrons

• Nearly accurate model till-then

Heisenberg's uncertainity principle

• The momentum of the electron

• Position of the electron

• Gave way for the Quantum theory of atomic structure.

Quantum Model of the Atom

• The probable presence of electrons can be predicted

• Generally present in orbitals, namely the s,p,d and f-orbitals

• Described as the balloon model.