Atomic Structure and the Periodic Table: Alpha Scattering Experiment Flashcards
What did the ancient Greeks believe about atoms?
- everything is made of atoms
- atoms are tiny sphere which cannot be divided
What model was introduced as a response to the discovery of electrons in the 19th century?
plum pudding model
Describe the plum pudding model.
Ball of positive charge with electrons embedded into it.
Why was the alpha scattering experiment done?
To test if the plum pudding model was correct
How was the alpha scattering experiment done?
Alpha particles were fired at a thing sheet of gold foil.
Why was gold used in the alpha scattering experiment?
It can be hammered out into a very thin foil
What were the results of the alpha scattering experiment?
- most of the alpha particles passed through the foil
- some were deflected and changed direction as they passed through the foil
- some bounced straight back off the gold foil
What did the fact that most of their alpha particles passing straight through the gold foil suggest?
Atoms are mainly empty space
What did the fact that some alpha particles were deflected show?
The centre of the atom must have a small concentrated positive charge that repelled the alpha particles (nucleus)
What did the fact that some alpha particles bounced straight back suggest about atoms?
The mass of the atom must be concentrated in the centre if the atom and have a positive charge that repelled them (the nucleus)
Describe the nuclear model.
- mostly empty space
- tiny positive nucleus in centre
- surrounded by electrons in a cloud
