Structure of the Atom

Discovering Charged Particles: The Journey from Dalton's Indivisible Atom to Modern Understanding

Welcome to Atomic Discovery

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Particle Colors
Proton (pāŗ)
Electron (eā»)
šŸ“š Understanding Charged Particles in Atoms

Key Concepts Summary

The Journey from Indivisible to Divisible:

Dalton's atomic theory proposed that atoms were solid, indivisible particles. However, experiments with static electricity revealed that atoms actually contain smaller charged particles that can be transferred between objects.

Discovery of Sub-Atomic Particles:
  • Electrons (eā»): Discovered by J.J. Thomson in 1897. These negatively charged particles have negligible mass and can be easily removed from atoms.
  • Protons (pāŗ): Discovered through Goldstein's canal ray experiments in 1886. These positively charged particles have approximately 2000 times the mass of an electron.
Modern Understanding:

Atoms consist of a dense nucleus containing protons, surrounded by electrons in orbital shells. The positive charges of protons balance the negative charges of electrons, making atoms electrically neutral overall.

Quick Facts to Remember:

ā€¢ Static electricity demonstrates electron transfer between atoms

ā€¢ Canal rays are streams of positive particles (protons) in gas discharge tubes

ā€¢ Atoms with equal protons and electrons have no net charge

ā€¢ Electrons can be removed from atoms more easily than protons