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28 Cards in this Set
- Front
- Back
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Definition of "mineral"
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A mineral is a naturally occurring solid with a highly ordered atomic arrangement and a definite (but not necessarily fixed), homogeneous chemical composition. Minerals are usually formed by inorganic processes.
Combination of structure and composition: a naturally (geologically) formed inorganic solid with a crystal structure and a homogeneous "definite" chemical composition. -Naturally formed (artificailly synthesized=synthesized minerals) -Solid, crystalline structure: atoms have fixed positions. Glass is amorphous, lacks a common structural unit. Minerals can show specific faces that result from underlying crystal structure. Most samples are somewhere in between. Their degrees of organization determine their physical properties. -Inorganic (some exceptions): biominerals: biologically formed minerals that have geologic counterparts -Definite Chemical composition: DISTINCT CATION TO ANION RATIO varying degrees of impurities and variation, but there are limits on the variation |
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8 most common minerals in Earth's crust
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O, Si, Al, K, Na, Fe, Mg, Ca
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Basis of the periodic table
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Elements in the same column have same number of electrons in valence shell, so they're chemically similar
Regular pattern to atomic/ionic radii down same column and across same row |
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Classification of minerals
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It is customary to classify minerals according to a scheme that incorporates both chemistry and structure.
After careful analysis, they are first classified by their anion or anionic group. This results in classifications, such as native elements, sulfides, oxides, carbonates, and silicates. Second in groups with many species and complex structures, such as the silicate group, further subclassifications are made that are primarily based on structural (atomic) arrangements, such as the various linkages of the silicate tetrahedra. According to one's use of minerals By analogy with chemical compounds |
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Types of bonds
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Covalent
Ionic Van der Waals Metallic |
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Covalent bonds
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Electron sharing
Occurs among atoms with high but similar electronegativities Polarized electro cloud produces highly directional bonds Lower symmetry than ionic bonds |
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Ionic bonds
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"an ionic bond forms when one or more electrons in the valence shell of an atom are transferred to the valence shell of another so that both elements achieve an inert gas configuration"
ions are simple spheres with a size/radius and a charge Lose or gain electrons to mimic noble-gas configuration non-directional bonding: high symmetry Shorter the bond length, stronger the bond => properties If difference in electronegativity is greater than or equal to 2 |
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Metallic bond
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"The attractive force between the positively charged nuclei with their filled electron orbitals (but lacking valence electrons) and the cloud (or sea) of negative electrons that hold such crystal structures together"
electrons de-localized. causes luster, electrical conductivity. Low but similar electronegativities. |
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Van der Waals bond
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does NOT involve valence electrons
weakest type, but still significant Force develops between electrically neutral clusters (molecules) due to slight imbalances in electron distribution ("residual charges") Observed in organic compounds graphite (between planes) |
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Hydrogen bonds
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2nd weakest type. Does NOT involve valence electrons. Develops if H is bonded to a strongly electronegative element (which "strips" hydrogen of its electron and leaves it with a local positive charge).
Molecule becomes polar, electrostatic attraction to negative ion in adjacent molecule. Dipole-dipole interactions ex. ice, layer silicate minerals such as clays |
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% bonding type: the ______ the electronegativity, the more ionic in character.
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greater
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Transition elements
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have multiple oxidation states/valence states
important causes of color |
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CN = 12
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cubic closest packed: ABCABC
hexagonal closest packed: ABABAB |
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CN=8
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Body centered cubic
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CN=6
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Octahedral
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CN = 4
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Tetrahedral (diamond)
Square planar (CaCO3) |
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CN = 3
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Trigonal
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CN=2
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Linear
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Forsterite
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Mg2Si04
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Fayalite
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Fe2SiO4
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Calcite
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CaCo3
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Anorthite
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CaAl2Si2O8
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Albite
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NaAlSi3O8
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Orthoclase
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KAlSi3O8
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Exsolution
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the process whereby an initially homogeneous solid solution separates into two or possibly more distinct crystalline minerals without the addition or removal of material to or from the system. This means that there is no change in the bulk composition
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Solvus
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a line (binary system) or surface (ternary system) on a phase diagram which separates a homogeneous solid solution from a field of several phases which may form by exsolution or incongruent melting.
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Electronegativity
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a measure of the ability of an atom in a crystal structure (or moluecule to gain (or lose) electrons to its outer shell
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Ionization potential
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energy required to remove the most weakly held electron from a neutral atom
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