A-LEVEL PHYSICS: 8.1.1: Rutherford Scattering (SaveMyExams)

Question 1

Rutherford passed beams of α particles through a thin sheet of gold foil to investigate: (2)

Answer 1

-the different angles of deflection of the α particles

-no. of α particles deflected at each angle

Question 2

setup for the scattering experiment consisted of: (4)

Answer 2

-source of α particles (in lead container)

-thin sheet of gold foil

-movable detector

-evacuated chamber

Question 3

purpose of lead container in scattering experiment:

Answer 3

to produce a collimated beam of α particles
(bc α particles are absorbed by lead)

Question 4

α particles are emitted in all directions, so the source was placed in a ___ ___

Answer 4

lead container

Question 5

purpose of thin sheet of gold foil in scattering experiment: (3)

Answer 5

-needed to be extremely thin (~10^-6m thin)

-bc any thicker foil would stop the α particles completely

-Gold was chosen due to its malleability, easier to hammer into thin sheets

Question 6

purpose of evacuated chamber in scattering experiment: (3)

Answer 6

• α particles are highly ionising, meaning they only travel ~5cm before interacting with air molecules

-so apparatus was placed in evacuated chamber, to ensure that the α particles did not collide with any air molecules on their way to the gold foil

Question 7

alpha (α) particle is…

Answer 7

nucleus of a helium atom

He 2+

Question 8

observations from Rutherford’s scattering experiment: (3) explain what each suggest about the structure of the atom:
what was the conclusion drawn?

Answer 8

-majority of α-particles passed straight through
-suggests the atom is mostly empty space

-some α-particles deflected back at small angles of <10°
-suggests there is a + nucleus at the centre (since 2 + charges repel)

-a small number of α-particles deflected straight back at angles >90°
-suggests the nucleus is v. small & is where most of the mass & charge are concentrated

conclusion: atoms consist of small, dense, + charged nuclei, surrounded by e-

Question 9

observation from scattering experiment: majority of α-particles passed straight through

what this suggest about the structure of the atom:

Answer 9

suggests the atom is mostly empty space

Question 10

observation from scattering experiment: some α-particles deflected back at small angles of <10°

what this suggest about the structure of the atom:

Answer 10

suggests there is a + nucleus at the centre (since 2 + charges repel)

Question 11

observation from scattering experiment: a small number of α-particles deflected straight back at angles >90°

what this suggest about the structure of the atom:

Answer 11

suggests the nucleus is v. small & is where most of the mass & charge are concentrated