C1.2.3 - Developing the Atomic Model Flashcards
What did Dalton suggest?
All atoms of an element are identical
Different elements obtain different atoms
All matter is made from atoms
Why did people believe Dalton?
He creat a model of an atom which supported his stamens and their previous ideas
When did Dalton produce this model?
1803
What is Dalton’s model called?
The Billiard Ball Model
The Dalton Model
The Solid Sphere Model
Why was Dalton’s model of the atom not very accurate?
He didn’t have much equipment to experiment
What did Thompson discover?
A new subatomic particles known as the electron
What were Thompson’s results during his experiments?
That beams of cathode rays changed the direction in electric and magnetic fields
What did Thompson conclude from the experiment results?
Cathode Rays were actually made up of tiny particles that were negatively charged and much smaller than atoms
What did Thompson show that was new in his model?
Electrons
The atom is neutrally charged
There is a positive mass somewhere
What was the name of Thompson’s model?
Plum Pudding Model
Thompson Model
When did Thompson create his model of the atom?
1904
What did Rutherford do?
He tested the plum pudding model by firing alpha particles at a piece of gold foil
What were the results of Rutherford’s model?
99% alpha particles went through
- 99% alpha particles veered off slightly
- 01% alpha particles bounced back
What did Rutherford conclude from his results?
There was something small and heavy in the atom, and that the atom is mostly empty. There is also a huge charge that is concentrated in a small space
How did Rutherford explain his conclusion?
He said there was a small positively charged nucleus in the centre if the atom with electrons circling around it, neutralising the charge of the atom
