UNIVERSITY OF SOUTH ALABAMA Last Time 1 GY 111 Physical Geology Lecture 6 Mineral Classification Atoms Atomic Particles z z z Elementary Chemistry atomic structure 2 Isotopes 3 The Periodic Table 4 Bonding Atoms Atomic Particles Atoms are composed of 3 fundamental particles 1 Protons 2 Neutrons 3 Electrons Protons Neutrons always reside in the center of the atom termed the nucleus Electrons are always located in the electron cloud in complex orbitals where they orbit the nucleus z The number of protons and neutrons in the nucleus is variable and defines the different chemical elements refer to the periodic table 1H1 2He4 6C12 Electron Cloud Electrons Nucleus Protons Neutrons Atomic Number Simple atomic structure Isotopes z The number of protons and electrons for an element does not vary but the number of neutrons can e g hydrogen 1H1 Stable 1H2 Atomic Weight 1H3 Level n Name of electrons 2n2 1 K 2 2 L 8 3 M 18 4 N 32 5 O 50 Source http www amptek com xrf 3 gif Unstable 1 The Periodic Table Chemical Bonding zOccurs through the action of the electrons in the outer shells of atoms zPartially filled shells are less stable higher energy than filled shells lower energy zChemical reactions forming molecules strive to fill shells in atoms Name of electrons 2n2 1 K 2 2 L 8 3 M 18 4 N 32 5 O 50 Bonding Chemical Bonding Bond Three Major types 1 Ionic bonding exchange of electrons between atoms to form ions 2 Covalent bonding sharing of electrons between atoms 3 Metallic bonding freely exchangeable electrons between nuclei Level n Mineral properties Ionic strong bond high melting points vitreous lusters higher solubility Covalent strong bonds hard minerals very high melting points vitreous adamantine lusters Metallic weak bonds low to high melting points metallic lusters electrically conductive Atomic Packing Today s Agenda 1 2 Crystal Chemistry Crystallography Mineral Classification classes 3 The Silicates The Issue How do you build 33 dimensional crystals minerals from atoms ions and molecules Web notes 5 2 Atomic Packing Atomic Packing Minerals are assembled according to exact chemical blueprints blueprints Minerals are assembled according to exact chemical blueprints blueprints and those blue prints are controlled by exact mathematical and physical laws Atomic Packing Atomic Packing 1 Atoms ions make up minerals 2 Atoms take up space 3 How do you pack differently sized atoms in space to make up minerals 3 dimensions 2 dimensions Source http www mines edu academic courses met mtgn311 visual html Source http www mines edu academic courses met mtgn311 visual html Crystal Structures Crystal Structures CaF2 Halite Fluorite Source http staff aist go jp NaCl Ca2 F Source www chm bris ac uk 3 Polymorphs Crystal Structures Two minerals with the same chemical composition but different crystal structures e g Graphite C These are pretty pictures only You do NOT have to know this stuff for the exam s Diamond C Crystal Structures Al2O3 CaCO3 Ruby Calcite Al3 O2 Source http staff aist go jp Source http staff aist go jp Crystal Structures Crystal Structures CaCO3 MgFeSiO4 Aragonite Olivine Ca2 O2 C4 Source http staff aist go jp Source http staff aist go jp Crystal Structures Ca2 O2 C4 4 Crystal Structures Why classify minerals K Mg Fe 3AlSi3O10 OH F 2 Source http staff aist go jp Biotite Source www icminerals com Source www icminerals com At last count there are well over 4000 distinct minerals minerals in our solar system Why classify minerals Source www csm jmu edu Why classify minerals Why classify minerals Mineral Classification They are composed of 90 elements as well as more complex ions like CO32 SO42 PO43 etc Source www webchem net csm jmu edu At last count there are well over 4000 distinct minerals minerals in our solar system 5 Mineral Classification Mineral Classification Quartz SiO2 Mineral Name Chemical Formula Mineral Classification Mineral Classification O2 Source http staff aist go jp Si4 O2 Chemical Structure Crystal Structure Mineral Classification Why classify minerals Class The simplest way to classify minerals is by their anionic composition Name Anion s Anion s Examples Dominant Bond Native Elements none Metals Gold Copper Silver SemiSemi metals Arsenic As NonNon metals diamond graphite sulfur Metallic II Sulfides S Pyrite Chalcopyrite Galena Covalent III Oxides Oxides hydroxides O2 OH hematite magnetite limonite IV Halides Cl Fl halite fluorite V Carbonates CO32 calcite aragonite malachite VI Sulfates SO42 gypsum anhydrite VII Phosphates PO43 apatite VIII Silicates SiO44 3000 i e most minerals I Largely Ionic Chalk board time 6 Silicate Classification Silicate Classification SiO44The basic silicate tetrahedra Silicate Classification The basic silicate tetrahedra ball and stick Silicate Classification Silicate Classification The basic silicate tetrahedra just sticks Silicate Classification All silicates have the basic tetrahedra in their structures but there are 7 distinct silicate classes Chalk board time 7 Today s Homework 1 Download and read web notes 5 Next Time Quiz 3 Volcanoes and volcanism 1 2 8
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