Question

Rutherford Alpha ($\mathrm{\alpha }$) particles scattering experiment resulted in the discovery of

• A. electron
• B. proton
• C. the nucleus in the atom
• D. atomic mass

Answer 1

The correct option is C

the nucleus in the atom

The correct option is (C).

Explanation of the correct option:

Conclusion of Rutherford alpha particle experiment-

1. Most of the space inside the atom is empty thus most of the - particles pass through the gold foil without deflecting.
2. Very few $\mathrm{\alpha }$-particles were deflected by the gold foil. This means there is a small positive center in the atom which deflected the $\mathrm{\alpha }$-particle.
3. A very small fraction of $\mathrm{\alpha }$-particles defected from their path this indicates that the mass of the atom and positive charge occupies a very small volume of space.

On these observations, Rutheford proposed a new atomic model which has the following features-

1. The atom consists of the positively charged center called the Nucleus in which most of the mass of the atom is concentrated.
2. The size of the nucleus is very small as compared to the whole size of the atom.
3. The nucleus is surrounded by the negatively charged nucleus which balances the positive charge of the nucleus.

Explanation of the incorrect option:

Option (A):

Electrons were discovered by J.J Thomson in a cathode ray experiment.

Option (B):

Protons were discovered by E. Goldstein in 1886 by explaining the electrical neutral nature of the atom in a cathode ray experiment.

Option (D):

Atomic mass was discovered by Dalton. Atomic mass is the total number of protons and neutrons in an atom.

Hence, Rutherford Alpha ($\mathrm{\alpha }$) particle scattering experiment resulted in the discovery of the nucleus in the atom.