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39 Cards in this Set
- Front
- Back
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hypothesized that everything is made of "uncuttable" parts
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democritus
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law of conservation of mass
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mass can neither be created or destroyed in ordinary chemical/physical reactions
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law of definite proportions
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a pure compound always contains the same elements in the same proportions by mass
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law of multiple proportions
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when elements combine to form more than one compound, the ratios of the masses can be expressed by a ratio of small whole numbers
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hypothesized billiard ball model
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john dalton
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john dalton's five rules
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1. all matter composed of tiny particles called atoms
2. atoms of given element same in size, mass and other properties 3. atoms cannot be subdivided, created or destroyed 4. atoms of diff. elements combine in simple whole number ratios 5. in chemical reactions, atoms are combined separated or rearranged |
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discovered positively charged particles (protons) by using tube filled with hydrogen gas
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eugene goldstein
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what goldstein discovered about proton
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had charge equal and opposite to that of electron
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discovered electrons are negative and rest of atoms is positively charged
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jj thomson
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how thomson discovered electrons
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using the cathode ray experiment
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what cathode ray experiment is
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cathode ray tube emits stream of electrons and made the stream of electrons move
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discovered the charge to mass ratio of an electron
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thomson
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confirmed electron carries negative electric charge and calculated magnitude of charge of e-
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millikan
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how millikan confirmed electron carries negative charge
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oil drop experiment
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calculated the mass of an electron and that e- in every atom
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millikan
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model where negatively charged electrons pictured as embedded in positively charged circular cloud
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plum pudding model -- kelvin
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discovered mass of atom is contained in positive nucleus
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rutherford geiger and marsden
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what rutherford geiger and marsden inferred about the space of an atom
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atom is mostly empty space
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who used gold foil experiment
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rutherford geiger and marsden
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how gold foil experiment worked
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shot positive charge alphaparticles at piece of gold foil and observed how some particles (few) were delfected
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what alpha particle is
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helium nucleus, no electrons, positive charge -- 2 protons, 2 neutrons
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nucleon
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anything in the nucleus
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nuclide
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an isotope
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isotope
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an atom with a different number of neutrons
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ion
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atom with different number of electrons
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used a model of hydrogen atom like sun circling around the sun (some planets higher energy, some planets lower)
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niels bohr
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the diff. levels of energy in bohrs model
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closer=lower, farther=higher
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created mathematical model that described electrons as waves (wave mechanical model)
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schroedinger
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proved that exact location of electrons can never be known (impossible to know both factors), instead found 95% probability
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schroedinger
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what an orbital is
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three dimensional region around nucleus that shows probable location of electron
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discovered neutron
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chadwick
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what chadwick discovered about the mass of a neutron
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same mass as proton, little bit bigger
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three subatomic particles of an atom
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electrons, protons, neutrons
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what make up protons and neutrons
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mesons, antineutrinos
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where protons located
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nucleus
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where electrons located
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outside of nucleus, in electron cloud
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where neutrons located
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in necleus
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neuclear forces between protons, protons and protons, neutrons and neutrons, neutrons
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same charges usually repel, but when protons/neutrons really close there are strong attractive forces between them, keep nuclear particles together
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definiton of one amu
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1/12 of a carbon atom
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