Sub-Atomic Particles – Protons and Neutrons

The video tutorial explores the discovery of subatomic particles, focusing on Goldstein's canal rays, which are positively charged particles known as anode rays. These rays, unlike cathode rays, travel in the opposite direction and are deflected by electric and magnetic fields. Thomson's work on the mass-to-charge ratio of these particles is discussed, along with Rutherford's discovery of the nucleus containing protons. The tutorial concludes with Chadwick's experiment that identified neutrons, neutral particles with a mass similar to protons, which contribute to atomic mass.

Who discovered canal rays and in which year?

• J.J. Thomson in 1897

• Eugen Goldstein in 1886

• James Chadwick in 1932

• Ernest Rutherford in 1911

What is the primary characteristic of anode rays?

• They do not produce fluorescence.

• They are positively charged particles.

• They travel in the same direction as cathode rays.

• They are negatively charged particles.

What did Rutherford discover about the atomic nucleus?

• It contains both protons and neutrons.

• It contains only neutrons.

• It contains only protons.

• It contains only electrons.

What was the mass discrepancy observed in helium atoms?

• Helium's mass is four times that of hydrogen.

• Helium's mass is equal to hydrogen's mass.

• Helium's mass is half that of hydrogen.

• Helium's mass is twice that of hydrogen.

What experiment did Chadwick perform to discover neutrons?

• He used a cathode ray tube.

• He bombarded beryllium with alpha particles.

• He used a gold foil experiment.

• He observed the deflection of anode rays.

What is a unique property of neutrons compared to protons and electrons?

• They are negatively charged.

• They are positively charged.

• They are lighter than electrons.

• They have no charge.

What happens to a free neutron over time?

• It transforms into a photon.

• It becomes a positively charged particle.

• It decays into a proton, electron, and neutrino.

• It remains stable indefinitely.