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Structure
Interesting Questions, Facts and Information
- There are a total of 10 general entries.
Special Topics
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 Interesting Questions, Facts, and Information
 Laws and Theories of Physics
| Which important scientist created the theory that electrons are located within a fixed distance from the nucleus on a certain energy level? | Theories of Matter
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N. Bohr. Energy level is a state with definite and fixed energy in which an electron is allowed to move.
Frederick Soddy. Frederick Soddy was the first to propose that the number of neutrons can vary from atom to atom within the same element.
H. Moseley. Mendeleev, Newlands, and Meyer worked towards creating a periodic table, but the concept of atomic number was developed by Moseley. Moseley's research with X-rays showed that the nucleus of each element has its own, unique positive charge. The positive charge increases one by one as the elements progress through Mendeleev's periodic table. Moseley was the first to recognize the relationship between atomic number and nuclear charge.
Neutrons. James Chadwick (1891-1974) modified Ernest Rutherford's model by demonstrating that atomic nuclei must contain heavy neutral particles in order for the nuclei to have the proper mass.
| What type of particles did Ernest Rutherford use in his 1911 experiment with gold foil? | Theories of Matter
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alpha particles. Alpha particle is basically the nucleus of a helium atom produced by radioactive decay of uranium.
| What did J.J. Thomson use in order to measure the mass of the atom and its electric charge in 1897? | Theories of Matter
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cathode ray tube. J.J. Thomson (1856-1940) used the most primitive tool of the listed above since he could not have an electronic microscope or a mass spectrometer at the time. CANDU is a Canadian-designed nuclear reactor system.
| Who was a Greek that severely criticized the theory of atoms in continuous motion and proposed the four-element theory of matter? | Theories of Matter
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Aristotle . The thory was based on the idea that all matter is made up of four basic substances: earth, water, air, and fire. Aristotle and his followers believed that each of these basic substances had different combinations of four specific qualities: dry, moist, cold, and hot.
| First of all, who named a single indivisible particle of matter an atom? | Theories of Matter
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Democritus. He believed that different atoms are of different sizes, have regular geometric shapes, and are in constant motion. He also believed that there is empty space betweeen atoms.
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