C1.2.3 - Developing The Atomic Model Flashcards
(23 cards)
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 created a model of an atom that supported his statements
When did dalton produce his model of the atom?
1803
What is dalton’s model of the atom called?
Billiard ball model
Dalton model
Why was dalton’s model of the atom very accurate?
He didn’t have much equipment to experiment
What did Thomson discover?
A new subatomic particle known as the electron
What were Thomson’s results during his experiments?
That beams of cathode rays changed direction in electric and magnetic fields
What did Thomson conclude from the experiment results?
That cathode rays were actually tiny particles that were negatively charged and much smaller than atoms.
What did Thomson have to show in his atom model?
Electrons
The atom is neutrally charged
What was the name of Thomson’s model?
Plum pudding model
Thomson model
When did Thomson create his model of the atom?
1897
What did Rutherford do?
He tested the plum pudding model with an experiment by firing alpha particles at a piece of gold foil
What were the results of rutherford’s model?
99% alpha particle went through
- 99% alpha particle veered off slightly
- 01% alpha particle bounced back
What did Rutherford conclude from his results?
That there was something very heavy and small 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 conclusions?
He said there was a small positively charged nucleus in the centre of the atom with electrons circling around it, neutralising the charge of an atom.
What was rutherford’s model called?
Planetary Model
When did Rutherford create his model of an atom?
1909
Who did Rutherford work with in his experiments?
Hans Geiger and Ernest Marsden
What did Bohr do?
Use mathematical models to improve Rutherford’s models
What did he add to Rutherford’s model?
Electron shells
When did Bohr create his model?
1913
What did Bohr use to improve rutherford’s model?
Mathematical models
What did Bohr realise?
Orbiting electrons would slowly spiral into the nucleus as opposites attract
