Topic 6 - Radioactivity - Atomic Structure Flashcards
What did Dalton propose in 1800 regarding atomic structure?
Everything was made of atoms.
Dalton’s atomic theory laid the groundwork for modern chemistry.
Who discovered the electron and in what year?
JJ Thomson in 1897.
This discovery led to the development of the Plum Pudding Model.
What is the Plum Pudding Model?
A model where negative electrons are dispersed in a sphere of positive charge.
This model represents the atom as having a neutral overall charge.
What major conclusion did Rutherford draw from the Gold Foil Experiment in 1911?
Most of the atom is empty space.
This was demonstrated by the deflection of alpha particles passing through gold foil.
What was the setup of the Gold Foil Experiment?
A radioactive sample emitting alpha particles directed at gold foil, with a lead block shield and zinc sulfide screen.
This setup allowed observation of particle deflection.
What did Rutherford conclude about the nucleus based on the Gold Foil Experiment?
The nucleus must be positive and contains most of the mass.
Positive alpha particles were repelled by the nucleus.
What year did Rutherford propose his atomic model?
This model introduced a positive nucleus at the center of the atom.
Fill in the blank: In Rutherford’s model, negative electrons exist in a _______ around the nucleus.
cloud.
This concept marked a significant shift from earlier atomic models.
Who produced the final model of the atom in 1913?
Bohr
What are the three main subatomic particles?
- Proton
- Electron
- Neutron
What would happen if electrons were attracted to the nucleus according to Rutherford’s theory?
The atom would collapse
What did Bohr conclude about the existence of electrons in an atom?
Electrons exist in fixed ‘orbitals’
Fill in the blank: The __________ is a subatomic particle with a positive charge.
Proton
Fill in the blank: The __________ is a subatomic particle with no charge.
Neutron
