Exploring the Cathode Ray Tube and the Discovery of Electrons

The video explains JJ Thompson's discovery of the electron in 1897 using the cathode ray tube experiment. It describes how Thompson's experiments demonstrated that cathode rays are composed of negatively charged particles, which are much smaller than atoms. This led to the conclusion that atoms contain tiny negatively charged particles, known as electrons. Thompson's findings challenged the existing atomic model by John Dalton, which viewed atoms as indivisible. Thompson proposed the Plum Pudding model, suggesting that electrons are embedded in a positively charged 'dough'. However, this model was later refined with the discovery of the atomic nucleus.

What was John Dalton's model of the atom in the early 1800s?

• Atoms are electrically charged.

• Atoms are made of electrons and protons.

• Atoms are indivisible and solid.

• Atoms are made of smaller subatomic particles.

What did JJ Thompson use to discover the electron?

• A particle accelerator

• A cathode ray tube

• A magnet

• A gold foil

What did Thompson observe when he connected the cathode ray tube to a power source?

• The tube exploded.

• A glowing spot appeared on the inside of the glass.

• Nothing happened.

• The metal pieces melted.

How did Thompson determine that the cathode ray was negatively charged?

• By using a thermometer.

• By observing the ray's attraction to a positively charged plate.

• By measuring the temperature of the ray.

• By observing the ray's color.

What happened to the cathode ray when Thompson placed a magnet around the tube?

• It bent upwards.

• It changed color.

• It bent downwards.

• It disappeared.

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What conclusion did Thompson draw about the size of the particles in cathode rays?

• They are the same size as electrons.

• They are a thousand times smaller than hydrogen atoms.

• They are larger than hydrogen atoms.

• They are the same size as hydrogen atoms.

What did Thompson find when he used different types of metal in the cathode tube?

• All metals produced the same cathode rays.

• Different metals produced different cathode rays.

• The cathode rays changed color.

• No cathode rays were produced.

What did Thompson's experiments suggest about the structure of atoms?

• Atoms are made of protons and neutrons.

• Atoms are electrically charged.

• Atoms contain tiny negatively charged particles.

• Atoms are indivisible.

What model did Thompson propose for the atom?

• The solar system model

• The plum pudding model

• The gold foil model

• The nuclear model

What did Rutherford's gold foil experiment reveal about the atom?

• Atoms are electrically neutral.

• Atoms are made of electrons and protons.

• Atoms have a small, dense, positively charged nucleus.

• Atoms are indivisible.

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