Question

We have learnt that every element is made up of tiny particles called atoms. Many scientists have proposed different models of the atom and were involved in the evolution of modern atomic theory. Search the Internet and create a presentation on the atomic theory timeline. Include the name and image of the scientist, name of the model, year of discovery, image of the model and any other important information about the model in the presentation.

Answer 1

Slide 1: Introduction

• Title: Timeline of Atomic Theory
• Objective: Understanding how our knowledge of the atom evolved over time through different scientific models.

Slide 2: Dalton's Solid Sphere Model

• Scientist Name: John Dalton
• Year: 1803
• Model Name: Billiard Ball Model (Solid Sphere Model)
• Key Information:
  • Matter is made of tiny, indivisible particles called atoms.
  • Atoms of the same element are identical in mass and properties.
  • Atoms cannot be created, divided, or destroyed.

Slide 3: Thomson's Plum Pudding Model

• Scientist Name: J.J. Thomson
• Year: 1807
• Model Name: Plum Pudding Model (Watermelon Model)
• Key Information:
  • Discovered the first subatomic particle: the electron.
  • Proved that atoms are divisible and contain negative charges.
  • Described the atom as a positive sphere with negative electrons embedded inside it.

Slide 4: Rutherford's Nuclear Model

• Scientist Name: Ernest Rutherford
• Year: 1911
• Model Name: Nuclear Model (Planetary Model)
• Key Information:
  • Conducted the famous Gold Foil Experiment.
  • Discovered that the atom has a tiny, dense, positive center called the nucleus.
  • Stated that almost all mass is in the nucleus, and electrons revolve around it like planets.

Slide 5: Bohr's Planetary Model

• Scientist Name: Niels Bohr
• Year: 1913
• Model Name: Bohr's Orbit Model
• Key Information:
  • Modified Rutherford's model to explain why atoms are stable.
  • Stated that electrons travel only in fixed, circular paths called orbits or energy shells.
  • Electrons can jump between shells by absorbing or releasing specific amounts of energy.

Slide 6: Quantum Mechanical Model

• Scientist Name: Erwin Schrödinger
• Year: 1926
• Model Name: Electron Cloud Model
• Key Information:
  • Stated that electrons do not move in exact paths like planets.
  • Introduced mathematical equations to track electron behavior.
  • We can only predict the probability of finding an electron in a specific region called an orbital (electron cloud).