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Chapter 2 Minerals. Matter Solid – rocks and minerals Solid – rocks and minerals Liquid – oceans, rivers, lakes Liquid – oceans, rivers, lakes Gas – atmosphere.

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Presentation on theme: "Chapter 2 Minerals. Matter Solid – rocks and minerals Solid – rocks and minerals Liquid – oceans, rivers, lakes Liquid – oceans, rivers, lakes Gas – atmosphere."— Presentation transcript:

1 Chapter 2 Minerals

2 Matter Solid – rocks and minerals Solid – rocks and minerals Liquid – oceans, rivers, lakes Liquid – oceans, rivers, lakes Gas – atmosphere Gas – atmosphere Nearly 4000 minerals on Earth Nearly 4000 minerals on Earth Building blocks – elements Building blocks – elements

3 Elements and the Periodic Table Copper, iron, silver, gold Copper, iron, silver, gold Element – substance that cannot be broken down into simpler substances by chemical or physical means Element – substance that cannot be broken down into simpler substances by chemical or physical means 112 known, 92 naturally occurring 112 known, 92 naturally occurring Rows – periods Rows – periods –Share maximum electrons in outer shell Columns – groups Columns – groups –Have similar properties

4 Elements and the Periodic Table 8 known elements make up most of Earths crust 8 known elements make up most of Earths crust –Oxygen (O) –Silicon (Si) –Aluminum (Al) –Iron (Fe) –Calcium (Ca) –Sodium (Na) –Potassium (K) –Magnesium (Mg)

5 Atoms Atom – smallest particle of matter that contains characteristics of an element Atom – smallest particle of matter that contains characteristics of an element –Nucleus – protons(+) and neutrons(=) Proton and neutron have about equal mass Proton and neutron have about equal mass –Atomic number – number of protons in the nucleus –Atoms have same number of protons and neutrons

6 Atoms How do we figure out number of neutrons? How do we figure out number of neutrons? Atomic mass minus (-) # of protons (atomic number) Atomic mass minus (-) # of protons (atomic number) 4.003 – 2 + 2 neutrons 4.003 – 2 + 2 neutrons

7 How many neutrons? How many protons are in this atom? What is its mass number? How many neutrons does it have?

8 Atoms Electrons – smallest of three fundamental particles Electrons – smallest of three fundamental particles –Located in energy levels – sphere shaped negative zone called electron cloud first energy level – 2 electrons first energy level – 2 electrons Second energy level – 8 electrons Second energy level – 8 electrons –Interactions among energy levels explains why atoms form compounds

9 Atom

10 Isotopes Isotopes – atoms with same number of protons but different numbers of neutrons Isotopes – atoms with same number of protons but different numbers of neutrons –Labeled using mass number Mass number – total mass of an atom (protons + neutrons) Mass number – total mass of an atom (protons + neutrons) Expressed in atomic mass units Expressed in atomic mass units –Radioactive decay – occurs with some isotopes whose nuclei are unstable Can be used to determine the ages of fossils, rocks and minerals Can be used to determine the ages of fossils, rocks and minerals

11 Isotopes Carbon has 15 different isotopes Carbon has 15 different isotopes Carbon 14 most commonly used for radioactive dating Carbon 14 most commonly used for radioactive dating

12 Why Atoms Bond Compounds – substance that consists of two or more elements that are chemically combined in specific proportions Compounds – substance that consists of two or more elements that are chemically combined in specific proportions –Form when atoms are more stable in a combined form –They gain, lose, or share electrons –Most stable elements – far right of periodic table Group 8A Group 8A Outer shell is filled Outer shell is filled –Atom undergoes changes to its electron structure to be more like atoms in Group 8A

13 Chemical Bonds Chemical Bonds – forces that hold atoms together in a compound Chemical Bonds – forces that hold atoms together in a compound –Ionic –Covalent –Metallic Properties of a compound are different than properties of elements in a compound Properties of a compound are different than properties of elements in a compound

14 Ionic Bonds Ionic Bonds – form between positive and negative ions Ionic Bonds – form between positive and negative ions –Ion – atom that has an electrical charge because of gain or loss of one or more electrons Atoms that lose electrons – positively charged Atoms that lose electrons – positively charged Atoms that gain electrons – negatively charged Atoms that gain electrons – negatively charged

15 Ionic Bonds Some compounds have mineral name and chemical name Some compounds have mineral name and chemical name –NaCl – sodium chloride; halite Na loses one electron – becomes + ions Na loses one electron – becomes + ions Cl gains one electron – becomes – ions Cl gains one electron – becomes – ions –Becomes table salt

16 Ionic Bonds Elements with ionic bonds – ionic compounds Elements with ionic bonds – ionic compounds –Rigid solids with high melting and boiling points –Poor conductors of electricity in solid state –When melted, great conductors of electricity Most contain elements from groups 1 & 2 reacting with groups 16 & 17 Most contain elements from groups 1 & 2 reacting with groups 16 & 17

17 Covalent Bonds Covalent bonds – form when atoms share electrons Covalent bonds – form when atoms share electrons –Have low melting and boiling points –Poor conductors of electricity –Silicon dioxide (SiO 2 ) – quartz One of most common covalent bonds on Earth One of most common covalent bonds on Earth One silicon and two oxygen atoms share electrons in outer shell One silicon and two oxygen atoms share electrons in outer shell

18 Covalent Bond

19 Covalent Bonds Molecule – smallest particle of a covalent compound that shows properties of that compound Molecule – smallest particle of a covalent compound that shows properties of that compound –Water – H 2 O molecules Two hydrogen atoms covalently bonded to an oxygen Two hydrogen atoms covalently bonded to an oxygen –Atmospheric gases - hydrogen, oxygen, nitrogen, and carbon dioxide consist of molecules consist of molecules

20 Metallic Bonds Metallic bonds – form when electrons are shared by metal ions Metallic bonds – form when electrons are shared by metal ions –Sharing of electron pool gives metals their characteristic properties Malleable – easily shaped Malleable – easily shaped Ductile – drawn into thin wires without breaking Ductile – drawn into thin wires without breaking Excellent conductors of electricity Excellent conductors of electricity

21 Minerals Mineral Mineral –Naturally occurring –Solid substance –Orderly crystalline structure –Definite chemical composition –Generally considered inorganic

22 Crystalline Structure

23 How Minerals Form Crystallization from Magma Crystallization from Magma –Magma cools – elements combine to form minerals

24 How Minerals Form Precipitation Precipitation –When water evaporates – substances react to form minerals –Changes in temperature – can cause substances to precipitate and form minerals

25 How Minerals Form Pressure and Temperature Pressure and Temperature –Increase in pressure: can cause mineral to recrystallize while still solid Atoms rearranged to form more compact minerals Atoms rearranged to form more compact minerals –Change in temp: cause certain minerals to become unstable New minerals form that are stable at that temp New minerals form that are stable at that temp

26 Meteor Crater - Arizona Quartz sandstone – at 500,000 psi is converted to coesite Quartz sandstone – at 500,000 psi is converted to coesite Meteor impact creates pressure Meteor impact creates pressure 1 st time element found in nature 1 st time element found in nature

27 How Minerals Form Hydrothermal solutions Hydrothermal solutions –Very hot mixture of water and dissolved substances When they come into contact with existing minerals – new minerals formed When they come into contact with existing minerals – new minerals formed

28 Mineral Groups Minerals – classified based on composition Minerals – classified based on composition Silicates – most common group Silicates – most common group –Silicon and oxygen Forms a silicon-oxygen tetrahedron Forms a silicon-oxygen tetrahedron One silicon and 4 oxygen atoms forms framework One silicon and 4 oxygen atoms forms framework –Most form from magma crystallization Some from weathering Some from weathering extreme pressures from mountain building extreme pressures from mountain building

29 Quartz

30

31 Silicates Different forms: Different forms: –Single tetrahedron: olivine –Single chains: augite –Double chains: hornblende –Sheets: mica –Three-dimensional networks: quartz, feldspar

32 Silicates

33 Carbonates Second most common mineral group Second most common mineral group Carbon, oxygen, and one or more metallic elements Carbon, oxygen, and one or more metallic elements –Calcite (CaCO 3 ) most common –Dolomite – magnesium and carbon –Limestone and marble –Used for building and construction

34 Limestone

35 Oxides Oxygen and one or more elements, usually metals Oxygen and one or more elements, usually metals –Some form from magma crystallization –Some form due to changes in temp and pressure Rutile (TiO 2 ) – titanium oxide Rutile (TiO 2 ) – titanium oxide Corundum (Al 2 O 3 ) – aluminum oxide Corundum (Al 2 O 3 ) – aluminum oxide Hematite (Fe 2 O 3 ) – iron oxide Hematite (Fe 2 O 3 ) – iron oxide –Existing minerals exposed to liquid water or moisture in the air

36 Sulfates and Sulfides Contain element sulfur Contain element sulfur Sulfates Sulfates –Anhydrite (CaSO 4 ) –Gypsum (CaSO 4 · 2H 2 O) –Form when mineral-rich waters evaporate Sulfides Sulfides –Galena (PbS) –Sphalerite (ZnS) –Pyrite (FeS 2 ) – Fools Gold, WWII sulfuric acid, car battery, explosives Fools Gold, WWII sulfuric acid, car battery, explosives –Form from thermal, or hot-water, solutions

37 Largest known crystals in the world Naica Mine, Mexico Naica Mine, Mexico Gypsum Gypsum Up to 50 ft. long, 4 feet in diameter Up to 50 ft. long, 4 feet in diameter

38 Halides Contain a halogen ion plus one or more other elements Contain a halogen ion plus one or more other elements –Halogens – elements from Groups 7A of periodic table Includes Fluorine (F), chlorine (Cl) Includes Fluorine (F), chlorine (Cl) –Halite – NaCl: table salt –Fluorite – CaF 2 : makes steel Forms when salt water evaporates Forms when salt water evaporates

39 Halite

40 Native Elements Minerals that exist in relatively pure form Minerals that exist in relatively pure form –Gold (Au) Jewelry, money Jewelry, money –Silver (Ag) –Copper (Cu) Electrical wiring, computers Electrical wiring, computers –Sulfur (S) –Carbon (C) diamond and graphite diamond and graphite –Drill bits, abrasives –Some form from hydrothermal solutions


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