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64 Cards in this Set
- Front
- Back
Rutherford
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discovered the atomic nucleus
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What experiments did rutherford perform to find the nucleus
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he shot alpha rays through gold foil to see if the ray went all the way through. what he discovered was that 99.9% of them all went through but the rest bounced back.
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What did the discovery of neutrons conclude?
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It is how elements can have different isotopes.
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What do electrons determine?
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It determines the chemical properties of an element.
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Atomic Number?
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number of protons in nucleus: determines number of electrons so determines
the chemical identity of the atom |
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Mass number?
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sum of protons and neutrons in the nucleus. Atoms with the same atomic
number but different mass numbers are isotopes of the same element |
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Avogadros number
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"mole"
finds a usable weight of an element. |
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λ
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wavelength
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John Dalton
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atomic theory
1808 used balance to weigh chemical reactions and their properties |
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What are the two parts to Dalton's atomic theory?
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1. Atoms all have characterisic masses.
2. Atoms combine in fixed ratios |
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Lavoisier
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fisrt to weigh chemical reaction
discredited the conservation of matter balance was enabling technology |
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Proust
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law of constant proportions
did similar experiment to lavoisier |
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William prout
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1816
came up with half weights and isotopes |
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Volta
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built the world's first battery
first supply of electrical current |
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How is Volta's battery constructed
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by layering Zn and Cu interchangeably. The metals don't touch.
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Discovery of X-Rays
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Wilhem Rontgen
1895 noticed zinc sulfide glowed in a cathode ray tube and placed a piece of cardboard between a tube and the mineral still glowed. |
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Discovery of Radioactivity
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1896
Bequerel exposed minerals to sun, wrapped them in photographic film, developed them later. the film was exposed even though it was not in the sun. |
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What conclusion did henri bequerel come to?
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That uranium minerals are radioactive
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Marie Curie
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A woman radiochemist that suspected other radioactive elements in uranium ore.
Extracted polonium and radium. |
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3 types of radiation
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alpha rays
beta rays gamma rays |
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alpha rays
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very weak, fast He nuclei
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beta rays
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more penetrating fast electrons
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gamma rays
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very penetrating, very high energy. used in x-rays
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ν
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frequency
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c
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speed of light
should be a given constant |
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diffraction
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classical experiment that shows the wave nature of light.
produce a series of light and dark fringes on a screen. |
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J.J Thompson
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discovered electron
1897 |
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J.J. Thompson's Cathode Ray Tube
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used in t.v. to produce screen.
helped discovered the electron by measuring the charge/mass ratio |
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Millikan
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1908-09
Performed oil-drop experiment |
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Oil drop experiment
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determined the mass of electrons by measuring their charge.
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Plum pudding model
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a mass of positive and negatively charge particles.
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ultraviolent catastrophe
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classical wave theory predicts that the light emitted
from a heated body would contain increasing amounts of energy as the wavelength gets shorter could not determine why this happens |
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Conservation of matter
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that the mass of reaction products is the sum of masses of the reagents, if
the experiment is done with sufficient care that all the reactants are accounted for. |
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Davy
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Electrolysis
discovered alkaline metals |
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E = mc2
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einestein's equation for the mass of energy
c=velocity of light |
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isotopes
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atoms with identical properties but different masses
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law of multiple porportions
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when elements combine to form more than one compound, the ratio of combining masses fo one of the elements would always be in the ratio of small whole numbers
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michael faraday
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discovered electrical power current
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Packing Fracture Curve
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measurements of the tiny mass
differences (per atomic particle or nucleon) for the easy elements to analyze |
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Proust
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demonstrated that for a given reaction the ratio of the reactant weights was a
constant |
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vacuum pumps
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1880
led to the discovery that an electric current could also be passed through a gas if a sufficiently high voltage was applied with the gas at a low enough pressure |
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What are some examples of exothermic energy?
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From the sun
Hydrogen bombs Hopefully in the future hydrogen fusion reactors |
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What did Aston's packing fracture curve make scientists realize?
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the enormity of the nuclear energy that could be released if, for example,
the heaviest nuclei could be broken up into smaller, lighter nuclei |
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What is produced when elements are fused together?
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Energy
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Why can nuclear fusion happen?
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Because heavier nuclei are stable than the lighter ones and allow elements to fuse together to create heavier ones
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Quantum Theory
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energy is discret packets
challenges ultraviolent catastrophe explains the power curve |
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Who first developed the quantum theory?
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Max Planck 1900
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Photoelectric effect
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energy increases as wavelengths get shorter
the maximum energy of the electrons increases as the wavelength of the light gets shorter. |
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Key details of the photoelectric effect
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1. electron current is proportional to the light intensity-but only if the wavelenght of light is shorter than some threshold
2. electron energy is proportional to 1/wavelength |
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Albert Einstein's explanation of photoelectric effect (1905)
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light acts as a series of
particles (now called photons) with energies proportional to the frequency |
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photons
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wave packets
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Bohr
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1913
applied quantum ideas to rutherford's nucleus non radiating orbits electrons orbit around nucleus |
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What did niels bohr suggest about the stable orbits around the nucleus of an atom?
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had quantized angular
momentum |
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What happend when light is absorbed by atoms?
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The electrons get excited and jump to a higher "n" value or higher shell away from the nucleus.
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What happens when light is emitted by atoms?
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The electrons jump to a lower shell closer to the nucleus.
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De Broglie
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standing waves
particles such as electrons might have wave-like properties uantized energy levels in atoms might have some association with standing waves suggested that particles should have a wavelength |
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Bohr
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1913
applied quantum ideas to rutherford's nucleus non radiating orbits electrons orbit around nucleus |
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v
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velocity
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What did niels bohr suggest about the stable orbits around the nucleus of an atom?
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had quantized angular
momentum |
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Heinsberg's uncertainty principle for energy/time
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Electrons only exist in excited states for a
short time covers a broad range |
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Heinsberg's uncertainty principle for position/momentum
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If we squeeze an electron into a smaller region of
space (make Δx smaller) its momentum uncertainty Δp increases total energy cannot be less than the energy uncertainty |
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waves
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characterized by their velocity, frequency, and length
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When do standing waves form?
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when a traveling wave is reflected so that the returning wave is exactly in phase with the arriving wave
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Schrodinger
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produced a wave equation which described an electron moving in 3
dimensions under the influence of the electrostatic attraction of the atomic nucleus |