P1.1 Particle Model

Question 1

Atom

Answer 1

Smallest particle of an element that can exist
Made of protons, neutrons and electrons

Question 2

Bohr model

Answer 2

Small DENSE nucleus surrounded by orbiting electrons with attraction provided by electrostatic forces

Question 3

Electron

Answer 3

Subatomic particle orbiting the nucleus of an atom
-1 charge
0.0005 or negligible relative mass

Question 4

Electron shells

Answer 4

Orbits around an atom by electrons in energy levels,
for electrons in the Bohr model

Question 5

Neutron

Answer 5

Subatomic particle found in nucleus of an atom
No charge
Relative mass of 1

Question 6

Nucleus

Answer 6

Small dense mass at centre of an atom made of protons and neutrons

Question 7

Order of magnitude

Answer 7

Number to the nearest power of 10
Increase of 2 orders = multiplying by 100

Question 8

Plum pudding model

Answer 8

Outdated model
Electrons embedded in a sphere of positive charge

Question 9

Proton

Answer 9

Subatomic particle in nucleus of the atom
Charge of +1
Relative mass of 1

Question 10

Rutherford model

Answer 10

Positively charged nucleus and electrons orbit around it

Question 11

How Rutherford’s observations led him to suggest that an atom has a nucleus

Answer 11

In the alpha particle experiment:
Majority of the alpha particles passed through with little or no deflection so the majority of the atom is empty space/vacuum
Few alpha particles were deflected backwards, showing that there is a small, massive nucleus at the centre
1 in 8000 was scattered through large angles so the mass of the atom is very concentrated at the centre of the atom
This mass (nucleus) is positively charged. This mass (the nucleus) is very small compared to the size of the atom.
There would not be any alpha particles scattered through large angles if the plum pudding model were correct

Question 12

Diameter of a typical atom

Answer 12

1 x 10 ^ -10 m

Question 13

Typical radius of a nuclei

Answer 13

10 ^ -15 m

Question 14

Observations of Rutherford, Geiger, and Marsden’s experiment

Answer 14

Majority of alpha particles passed through with little or no deflection so the majority of the atom is empty space/vacuum

Few alpha particles were deflected backwards, showing that there is a small, massive nucleus at the centre

1 in 8,000 was scattered through large angles

Question 15

Conclusions from Thomson’s experiments with cathode rays

Answer 15

Cathode rays were made of negatively charged particles - electrons
The particles had a mass smaller than an atom
Atoms were neutral in charge

Question 16

Difference between the Democritus model of the atom and Dalton’s

Answer 16

There was no scientific equipment to do experiments on atoms
Democritus thought that there were atoms because of a BELIEF he had about the nature of matter
Dalton’s model was a simple solid sphere
The sphere for one element was different from the sphere for another but he did not know how

Question 17

How does the cathode ray tube work

Answer 17

Metal cross at front is heated to release electrons
These electrons cause fluorescent light
The light can be attracted or repelled using magnets
Cathode is negatively charged to repel electrons to the anode
This is done in a vacuum to avoid collision with air particles

Question 18

Charge of the cathode and anode

Answer 18

Cathode - negatively charged
Anode - positively charged

Positive
Anode
Negative
Is
Cathode