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Published byJulissa Game Modified over 9 years ago
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Physical Geology Chapter 4
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Matter Anything that has mass and volume Elements = simplest stable form of matter Made of atoms Compounds = chemically combined elements Made of molecules Elements:atoms::compounds:molecules
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98% of crust is 8 elements and their compounds
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Atomic Structure Small electrons in cloud (- charge) Much larger protons in nucleus (+ charge) Slightly larger neutrons in nucleus (0 charge) Every element unique
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Common units of mass, such as grams, are much too large to conveniently describe the mass of an atomic nucleus or any of its constituent parts. To solve this problem a new unit was defined: the atomic mass unit (amu). The atomic mass unit is a relative unit defined arbitrarily by assigning a mass of 12 amu to the neutral atom carbon-12, the common isotope of carbon. One atomic mass unit equals 1.66 X 10-24 grams. Employing this value, the masses of the fundamental particles of an atom have been determined to be: (1) Proton mass: 1.00727 amu. (2) Neutron mass: 1.00867 amu. (3) Electron mass: 0.00055 amu.
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= atomic number
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= atomic mass
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Forms of the same element Differ in # of neutrons Same atomic number but different atomic mass (heavier) Similar behavior with some different properties Leads to average atomic mass H = 1.00794 amu
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Ions
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Valence electrons create behaviors/properties and establish periodic groups on table
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Metals have 1-3 valence electrons and lose them easily Non-metals have 4-7 electrons and tend to gather more
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Mendeleev’s Table
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2 and 8 electrons create unreactive state (Happy) Is this important?
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How do they become “happy”? Chemical bonding!
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Ionic bond – giving/taking e-
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Covalent bond – sharing e-
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Polar covalent molecule + _
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Mixtures Unlike a compound, the components are not chemically combined, just physically combined Heterogenous – not equally mixed Homogenous – “solution” and equally mixed
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