C1.5 (HIstory of the atom) Flashcards
1
Q
What was Dalton’s theory
A
Substances are made of atoms that are tiny hard spheres
2
Q
Dalton believed that atoms can’t be ………
A
split
3
Q
Who discovered the electron
A
J.J Thompson
4
Q
What is the (relative) mass of an electron
A
1/1836
5
Q
What experiment found electrons
A
Cathode rays
6
Q
What type of atom did J.J Thompson theorise
A
The Plum Pudding Model
7
Q
What was the Plum Pudding Model
A
Thought that negative electrons are embedded in a positive nucleus
8
Q
How does the Cathode ray experiment work
A
- High voltage to gas at low pressure
- glass glows struck by rays
- rays from cathode are electrons
9
Q
How does the Gold foil experiment work
A
- Alpha particles shot at gold foil
- Not all particles pass straight through
10
Q
What did the Gold foil experiment suggest
A
- The mass of an atom is concentrated at the centre
