Question

2.Explain Rutherford's alpha scattering experiment with well labelled diagram. write its
limitations.​

Answer 1

Answer:

Rutherford’s conducted an experiment by bombarding a thin sheet of gold with α-particles and then studied the trajectory of these particles after their interaction with the gold foil.

Rutherford Atomic Model

Rutherford, in his experiment, directed high energy streams of α-particles from a radioactive source at a thin sheet (100 nm thickness) of gold. In order to study the deflection caused to the α-particles, he placed a fluorescent zinc sulphide screen around the thin gold foil. Rutherford made certain observations that contradicted

Limitations of Rutherford Atomic Model

Although the Rutherford atomic model was based on experimental observations it failed to explain certain things.

Rutherford proposed that the electrons revolve around the nucleus in fixed paths called orbits. According to Maxwell, accelerated charged particles emit electromagnetic radiations and hence an electron revolving around the nucleus should emit electromagnetic radiation. This radiation would carry energy from the motion of the electron which would come at the cost of shrinking of orbits. Ultimately the electrons would collapse in the nucleus. Calculations have shown that as per the Rutherford model, an electron would collapse in the nucleus in less than 10-8 seconds. So Rutherford model was not in accordance with Maxwell’s theory and could not explain the stability of an atom.

One of the drawbacks of the Rutherford model was also that he did not say anything about the arrangement of electrons in an atom which made his theory incomplete.

Although the early atomic models were inaccurate and failed to explain certain experimental results, they were the base for future developments in the world of quantum mechanics.

Answer 2

Answer:

Rutherford passed beams of alpha particles through a thin gold foil to observe the atom and noted how the alpha particles scattered from the foil.

Observations of Rutherford's alpha ray scattering experiment:

1.Most of the α-particles passed straight through the gold foil without any deviation.

2. Some of the α-particles were deflected by the foil by some angles.

3.Interestingly one out of every 12,000 alpha particles appeared to rebound

Conclusion of Rutherford's scattering experiment:

1.Most of the space inside the atom is empty because most of the α-particles passed through the gold foil without getting deflected.

2. Very few particles were deflected from their path, indicating that the positive charge of the atom occupies very little space.

3. A very small fraction of α-particles were deflected by very large angles, indicating that all the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.

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