Atoms Flashcards
1
Q
Who’s jj thompson
A
Made plum pudding
= atom is ball of positive charge with sea of negative electrons
2
Q
Who’s Rutherford
A
Fired alpha particles at thin gold
= particles reflected and deflected
Suggest nuclear model
= positive nucleus surrounded by cloud of negative charge
3
Q
Who’s Bohr
A
Positive nucleus with orbiting shells of electrons to prevent atom from collapsing
4
Q
Who’s Rutherford
A
Proved that nucleus made of protons
5
Q
Who’s Chadwick
A
Proved neutrons
6
Q
How do unstable isotopes stabilise
A
Releasing radioactive radiation
7
Q
Define half life
A
Time taken for number of radioactive nuclei in a sample to halve
8
Q
How to record decays
A
Geiger muller tube and counter
= record decays that reach them each second
9
Q
How to find out whether atom is alpha or beta radiation
A
- place GM tube and counter at at fixed distance apart
- absorb material
- alpha count will decrease rapidly when distance exceeds 5cm
