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30 Cards in this Set
- Front
- Back
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Which ancient greek philosopher came up with the word "atomos"?
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Democritus
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What are Dalton's 4 postulates of his proposed atomic theory?
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1. All elements are composed of atoms
2. All atoms of an element are identical 3. In chemical reactions, atoms are not changed. 4. In a compound, atoms combine in different orientations |
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What is the Law of Constant Composition?
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In a given compound, the relative numbers and kinds of atoms are constant.
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What is the the Law of Conservation of Mass (Matter)?
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The total mass of materials present after a chemical reaciton is the same as the total mass present before the reaction.
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What is the law of Multiple proportions
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If two elements A and B combine to form more than one compound, the masses of B that can combine with a given mass of A are in the ratio of small whole numbers (AKA NO FRACTIONS)
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Subatomic particles
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Those particles that make up the atom
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What is the law of electrostatic attraction?
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Like charges repel, and opposite charges attract
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What are cathode rays?
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The radiation produced when high voltage is applied to electrodes in a cathode ray tube. (ELECTRONS)
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What is so cool about the charge to mass ratio?
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it shows that all electrons are the same
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What did the millikan oil drop experiment, what did show, and what did Millikan infer about electrons with the charge to mass ratio?
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It showed the charge of an electron, and he was able to calculate the mass.
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What is radioactivity?
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Spontaneous emission of radiation
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What were the 3 spots observed in the radioactivity experiment?
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1. A spot deflected in the direction of the positive plate, is negatively charged, Beta rays. (ELECTRONS).
2. A spot that is not affected by the electric field, gamma rays. (X-RAYS) 3.A spot deflected in the direction of the negative plate, it's alpha rays. (POSITIVE CORE OF HELIUM ATOM) |
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How did they determine that alpha rays were heavier than Beta rays?
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They didn't travel as far when deflected.
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What did Rutherford disprove with his goldfoil experiment?
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The plumpudding model of the atom, because alpha particles passed thorugh the thin gold foil, which showed that there is a nucleous that is really small, but sometimes, they reflected back.
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Do atoms have a net electrical charge?
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No they are neutral b/c electrons have -1.6x10^-19 and protons have +1.6x10^-19. They "cancel" out.
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What is the atomic mass unit and why do we use it?
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Because the masses of atoms are so small, we use amus. It is the way we measure the weight of protons, neutrons, and electrons.
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Where is almost all the mass in an atom?
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nucleus
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What is an angstrom?
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Way of measuring the diameters of atoms
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What is the atomic number?
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# of protons in the nuecleus
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What is the mass number?
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Total number of protons and neutrons in the nucleus
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What are isotopes?
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Atoms that have the same number of protons, but variable numbers of neutrons
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What is a nuclide?
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An atom of a specific isotope
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What is the average atomic mass?
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After averaging the masses of isotopes to give average atomic masses. Equal to the wieghts of the isotopes as a function of their percentages.
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What is the periodic table used for?
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to organize the elements in a meaningful way
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What are the rows of the periodic table called?
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periods
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What are the columns in the periodic table called?
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groups
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Where are the metallic elements located
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in the left part of the periodic table
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Where are the nonmetallic elements located
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On top right of periodic table
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Where are the metalloids located?
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Interface between metals and nonmetals
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What is a molecule?
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two or more atoms that are tightly bound together.
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