Question

6. State the observations from the a-particle scattering experiment which led Rutherford
to make the following conclusions:
(3)
a. Most space in an atom is empty.
b. Entire mass of an atom is concentrated at its centre.
c. Centre is positively charged.​

Answer 1

Answer:

The observations are as follows:

a) He noticed that most of the alpha particles passed through the gold foil undeviated, which made him conclude that most of the space inside an atom is empty.

b) A few alpha particles ( ~1 in 20,000) were deviated by 180°, that is they retreated on the path they came from. This shows that the mass of the atom is concentrated in very small space, which we call the nucleus.

c) Since alpha particles are also positively charged particles, and they were repelled by the atoms of the gold foil, it shows that the centre of the gold atom which repelled the alpha particles must also be positive.