Question

Rutherford’s ‘alpha (α) particles scattering experiment’ resulted in to the discovery of :

• A. Electron
• B. proton
• C. nucleus in an atom
• D. Atomic mass

Answer 1

The correct option is C

nucleus in an atom

The explanation for the correct option:

Option C

Rutherford's model of an atom:

• The whole mass and positive charge of an atom are concentrated in a very small region at the center known as the nucleus.
• The positive charge on the nucleus is due to protons. The number of protons is different for atoms of different elements, therefore, the magnitude of positive charge on the nucleus is different for atoms of different elements.
• The nucleus is surrounded by negatively charged particles called electrons.
• The number of electrons in an atom is equal to the number of protons (positively charged) in the nucleus. Thus, the atom as a whole is neutral.

Therefore, option C is correct.

The explanation for the incorrect option:

Option A

• Electrons are negatively charged particles that revolve around the nucleus in a circular path called an orbit.
• Electron was discovered by J.J Thomson.

Therefore, option A is incorrect.

Option B

• Protons are positively charged particles present in the nucleus.
• Proton was discovered by E. Goldstein.

Therefore, option B is incorrect.

Option D

• The Sum of protons and neutrons is called atomic mass or mass number.
• Atomic mass can be defined as $\frac{1}{12}\mathrm{th}$ the mass of a carbon -12 atom in its ground state.
• It is expressed in amu or u (unified).

Therefore, option D is incorrect.