NCERT Question 15 - Chapter 4 Class 9 - Structure of Atom

Rutherford’s alpha-particle scattering experiment was responsible for the discovery of

(a) Atomic Nucleus       (b) Electron

(c) Proton                     (d) Neutron

Answer

(a) Atomic Nucleus

Explanation -  

• Proton and Electron were known before Rutherford’s experiment.
• The existence of neutrons was not known.
• It was only known after Rutherford’s alpha-particle scattering experiment that the Atomic nucleus existed.
• In the experiment a fraction of the particles bounced back at an angle of 180 o proving that nearly all the mass of an atom is contained in the nucleus.