3. Discovery of Protons-Anode Rays/Canal Rays

Who discovered canal rays (anode rays)?

Eugen Goldstein in 1886.

What are canal rays?

Positively charged rays that travel from anode to cathode in a vacuum tube.

How were canal rays discovered?

Using a perforated cathode, Goldstein observed rays passing through the holes toward the cathode.

What determines the nature of canal rays?

The type of gas present in the discharge tube.

What did J.J. Thomson contribute to the study of canal rays?

He found that canal rays were made of positively charged ions, and identified the lightest ion from hydrogen gas.

What is the lightest ion found in canal rays?

The hydrogen ion (H⁺), which became identified as the proton.

Who formally discovered the proton?

Ernest Rutherford in 1917.

How did Rutherford discover the proton?

By bombarding nitrogen gas with alpha particles, he observed the production of hydrogen nuclei (protons).

What is the charge and mass of a proton?

Charge: +1e, Mass: 1837 times the electron’s mass.

Where are protons found in an atom?

In the nucleus.

What did canal rays help discover about atomic structure?

They led to identifying positive charges in atoms and the concept of the proton.

How are protons related to the element?

The number of protons (atomic number) determines the element.