Term
Format:
name - date (of discovery; got famous; only need year) |
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Definition
discovery / why famous
describe experiment |
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Term
| Erwin Schrordinger - 1926 |
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Definition
| He used the quantom theory to write and solve a mathematical equation describing the location and energy of an electron in a hydrogen atom. Also, the modern description of the electrons in atoms, the quantom mechanical model, comes from the mathematical solutions to the Schrodringer equation. Not a tangable experiment, calculated completely through mathematics. |
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Term
| Robert A. Millikan - 1916 |
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Definition
Carried out experiments that allowed him to find the quantity of charge caried by an electron. He also determined the ratio of the charge to the mass of an electron. millikan used these 2 values to calculate an accurate value for the mass of the electron.
<<<<<-----find what experiment envolved---->>>> |
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Definition
He constructed and organized the first logical periodic table of elements. He listed the elements in columns in order of increasing atomic mass; then he arranged the columns so that the elements with the most similar properties were side by side.
Pg. 123 |
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Term
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Definition
| He calculated the atomic number of the atoms of the elements. He then arranged the elements in a table by order of atomic number instead of atomic mass. |
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| Joseph John Thomson - 1897 |
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Definition
The English physicist discovered electrons. He performed an experiment that involved passing electric current through gases at low pressure. The gases and electric current were placed in a cathode ray tube.
Pg.110 |
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Definition
Used the gold foil experiment. He proposed that the atom is mostly empty space. He experimented by pointing alhpa waves at a sheet of gold and the alpha waves, which are helium atoms that have lost their 2 electrons, passed through the gold, or deflected at different angles at the sheet that was surrounding the experiment. He then discovered the nucleus. Through indirect evidence, he found that the nucleus is mostly empty space. Major contributor to the atomic theory.
Pg.111 |
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Definition
| Discovered the neutron. Neutrons were produced when beryllium-9 was bombarded with alpha particles. |
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Definition
Discovered the proton. Observed a cathode-ray tube and found rays traveling in the direction opposite to that of the cathode rays.
<<<---detail experiment--->>> |
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Term
| John Dalton - early 1800's |
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Definition
Formulated and Hypothesised Dalton's Atomic Theory.
- atoms of same element are all identical. Atoms of 1 element are different of atoms of another elements.(modified today to include neutrons)
- all elements are composed of indivisible, called atoms (false today)
- chemical reactions occur when atoms are groupped together or pulled apart. (true today)
- atoms of different chemicals can physically mix together or can chemically combine with one another in simple whole-number rations to form compounds.
He studied the ratios in which elements combine in chemical reactions.
pg. 107-8 |
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Term
| Democritus - 4th Century B.C. |
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Definition
| Suggested the existance of atoms, an invisible particle that are indivisible and indestructable. He did not do an experiment. |
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Definition
| Came up with the new atomic model, called the planetary model. He proposed that electrons are arranged in concentric circular paths, or orbits, around the nucleus. He pattered this model after the motions of the planets' motion around the sun. Also he proposed that the electrons in a particular path have a fixed energy; they cannot lose this energy, thus not being able to fall into the nucleus. |
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