Discovery of Atom Parts, OpenStax Flashcards
Like atoms are a substructure of matter…
Electrons and nuclei are substructures of the atom.
Positive charge is associated with…
Nuclei.
Negative charge is associated with…
Electrons.
What are gas discharge tubes?
They consist of an evacuated glass tube containing two metal electrodes and a rarefied gas. When a high voltage is applied to the electrodes, the gas glows.
What are Crookes tubes?
Crookes tubes are wherein electrons are freed from atoms and molecules in the rarefied gas inside the tube and are accelerated from the cathode (negative) to the anode (positive) by the high potential.
Cathode rays…
Collide with the gas atoms and molecules and excite them, resulting in the emission of electromagnetic radiation that makes the electron’s path visible as a ray that spreads and fades as it moves from the cathode.
Gas discharge tubes are most commonly called…
Cathode ray tubes, because the rays originate at the cathode.
J. J. Thomson…
Improved and expanded the scope of experiments with gas discharge tubes.
How did Thomson measure the ratio of the charge of the electron to its mass?
qe / me
Was it shocking or not shocking that there were bodies smaller than atoms?
It was very shocking. Thomson himself said that he only published this belief when the experiment left no escape from it.
What is the Millikan oil drop experiment?
Invented by Robert Millikan. Produced the first accurate direct measurement of the charge on electrons.
What happens in the Millikan oil drop experiment?
Fine drops of oil are sprayed from an atomizer. Some are charged by the process and can then be suspended between metal plates by voltage between the plates. The electric field is produced by the applied voltage.
The electron only has…
A tiny fraction of the mass of an atom. The nucleus contains most of the mass.
All electrons…
Are identical to one another.
Who is the father of nuclear physics?
Lord Ernest Rutherford.
