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58 Cards in this Set
- Front
- Back
500 BC coined the term "atomos"
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Democritus
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1770's Law of Conservation of Matter
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Lavoisier
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1799 Law of Definite Proportions
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Proust
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1802 Law of Multiple Proportions & proposed the first Atomic Theory
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Dalton
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1897 discovered the electron
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Thomson
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1911 used the gold foil experiment to show the existence of a small, dense center (the nucleus)
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Rutherford
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1911 used the oil drop experiemnt to calculate the mass of the electron
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Millikan
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1913 proposed the model of orbiting electrons which would not lose energy and "fall" into the nucleus
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Bohr
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1916 reported the values of the charge and mass of the electrons
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Millikan
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1919 research lead to the discovery of the proton & performed earliest articificial transmutation
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Rutherford
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1932 discovered the neutron
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Chadwick
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1886 discovered the canal rays (later found to be protons)
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Goldstein
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transmutation
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shooting alpha particles into different isotopes to form new isotopes that break down
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modern atomic theory/model
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Quantum Mechanical Model
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Law of conservation of Mass
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(Lavoisier) matter cannot be created or destroyed
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Law of Definite Proportions
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(Joseph Proust) proportions by mass of the elements in a given compound is always the same [e.g. water 1:8]
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Law of Multiple Proportions
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(Dalton) if two or more different compounds composed of the same two elements are analyzed, the masses of the second elemnt combined with a fixed mass of the first can be expressed as a ration of small whole numbers
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Dalton's Atomic Theory
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-elements composed of atoms which are indivisible particles
-atoms of same element are alike -atoms of different elements have different masses -compounds are formed by atoms of 2+ elements combining in definite whole number ratios |
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atom
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smallest particle of an element that still reatins the properties of that element
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electron cloud
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outer region containin 7 energy levels
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nucleus
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center core of the atom containing protons and neutrons
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3 main subatomic particles (even though there are 100+ known subatomic particles)
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protons (+) neutrons electrons (-)
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quarks
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make up protons and neutrons
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lepton
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group electrons belong to
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antiparticle
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exact opposite in charge for every quark and lepton
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1st subatomic particle discovered (when, by who, and how)
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electron 1897 Thomson using the discharge tube (Crooke's tube, Cathode Ray tube)
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electron charge measured by (who and experiment)
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Millikan and the oil drop experiment
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number of electrons in an atom determines:
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physical and chemical properties
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periodic law
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the elements are arranged in order of increasing atomic number; there is a periodic repition of their physical and chemical properties
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proton
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one of the nucleons made up of two up quarks and one down quark p=uud
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nucleus discovered (who and how)
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Rutherford with the gold foil experiment
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neutrons mass is _________ than protons mass
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slightly greater
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neutrons discovered (by and how)
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Chadwick in transmutation experiment
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when neutron decays...
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a proton, electron, and antineutrino are released
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neutrons made up of
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one up quark and two down quarks n=udd
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isotopes
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different numbers of neutrons in an element
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natural isotopes (#)
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250
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man-made isotopes (#)
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1000+
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atomic number (letter representation)
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number of protons in the nucleus of the atom of that element (Z)
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electrons and protons equal in ________ atoms
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neutral
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mass number (letter representation)
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total number of protons and neutrons in the nucleus (A)
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amu
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atomic mass unit= 1/12 mass of Carbon-12
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a relative mass is reported in which each proton and neutron is given the value of
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1
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mass not a whole number b/c of
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isotopes (average of all naturally occuring isotopes
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periodic table developed by
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Mendelev
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Moseley arranged elements by...
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nuclear charge/atomic number
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horizontal rows
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periods
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vertical columns
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groups/families
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metals
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left of stairstep
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nonmetals
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right of stairstep
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metalloids
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touching stairstep except Aluminum
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representative elements
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A's
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alkali metals
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group 1
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alkaline earth metals
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group 2
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halogens
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group 7
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noble gases
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group 8
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transition metals
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B's
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inner transition metals (location and other name)
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excert (rare earth elements)
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