Atomic Theory Development Flashcards
(20 cards)
Who proposed the Nuclear Model of the atom?
Ernest Rutherford
Proposed in 1909.
What are the small discrete particles in the atom?
Protons
They are part of the Nuclear Model.
What neutral particles were discovered?
Neutrons
Discovered by James Chadwick.
What atomic theory did Democritus propose?
Atomic Theory
Proposed around 500 B.C.
What model did John Dalton propose?
Solid Spheres
Proposed in the 1800s.
What model did J.J. Thomson introduce?
Plum Pudding Model
Introduced in 1897.
What concept did Niels Bohr introduce in 1913?
Electron Shells
Prevents the atom from collapsing.
Who discovered protons?
Ernest Rutherford
Key figure in atomic theory.
Who discovered neutrons?
James Chadwick
Important contribution to atomic structure.
What experiment did Ernest Rutherford conduct?
The Alpha Scattering Experiment.
What did Rutherford’s assistants fire at the gold foil?
Alpha particles.
What was the result of most alpha particles in the experiment?
Most alpha particles passed straight through the gold foil.
What does it mean if most of the alpha particles passed through the gold foil?
It means that most of the atom is empty space.
What happened to some alpha particles during the experiment?
Some alpha particles bounced back.
What does it indicate if some alpha particles bounced back?
It indicates that most of the mass is concentrated at the centre (nucleus).
What happened to some alpha particles that were deflected?
They changed direction.
What does deflection of alpha particles suggest about the nucleus?
It suggests that the nucleus is positively charged.
What model did Rutherford propose based on his findings?
The Nuclear model.
What are the key features of the Nuclear model?
- Mostly empty space
- Mass concentrated in the centre (nucleus)
- Nucleus is positively charged.
What was the previous model before the Nuclear model?
The Plum pudding model.
