Chapter 5: Atoms to Minerals

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Chapter 5 Atoms to Minerals
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5.1 Matter and Atoms

• KEY IDEA
• Ordinary matter is composed of elements, which
  are made up of tiny particles called atoms.
• Objectives
• I.D. characteristics of matter
• Compare particles that make up atoms of elements
• Describe the 3 types of chemical bonds

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What is Matter?

• Matter the substance of which any physical
  object is composed

• States of Matter
• Solid
• Liquid
• Gas

• Controlling factors
• Temperature
• Pressure

Examples Gold Mercury Oxygen
solid liquid gas
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The stuff that makes up all matter

• The make-up of solid matter on Earth

Atoms ? Elements ? Compounds ? Minerals ?
Rocks (smallest)
(largest)

• Elements
• fundamental building blocks
• smallest matter that cant be broken down

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Periodic Table of Elements
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The stuff that makes up all matter

• The make-up of solid matter on Earth

Atoms ? Elements ? Compounds ? Minerals ?
Rocks (smallest)
(largest)

• Atoms
• the stuff that builds elements
• the smallest particle that uniquely defines an
  element

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Atomic Structure

• Particles that make up an atom
• Protons positive () charge
• Neutrons no charge
• Electrons negative (-) charge
• Protons neutrons define the nucleus of an atom.
• Layers of electrons that orbit around the nucleus
  are called orbitals or energy-level shells.

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Atomic Structure
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Classifying AtomsPeriodic Table of Elements
Atomic Number ( of protons)
Mass number protons neutrons


YES These are called isotopes. Example
(Carbon) 12C 13C 14C
Can atoms of the same element have different mass
numbers?
Atomic weight protons average
neutrons
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Atomic Structure

• Atoms of the same element
• have the same number of protons (i.e., same
  atomic number)
• can have different numbers of neutrons (referred
  to as isotopes)
• can have different numbers of electrons

• Ion an atom that has gained or lost an electron

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Atomic Structure
Sodium atom loses an electron (becomes
positively charged)
Chlorine atom gains an electron (becomes
negatively charged)
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Bonding of Atoms? Compounds ?

• Definition
• A chemical compound consists of elements that
  combine in a specific ratio.

Examples NaCl H2O

• The smallest quantity of a compound is called a
  molecule.
• Molecules are held together by chemical bonding.

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Bonding chemical matrimony

• Chemical bonding
• formation of a compound by combining two or more
  elements
• manner in which electrons are distributed among
  atoms

• In bonded atoms, electrons may be lost, gained,
  or shared.

• 3 types of bonding
• ionic covalent metallic

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Bonding chemical matrimony

• Ionic bonding
• electrons are transferred between atoms forming
  attracting ions (e.g., NaCl)

Na
Cl
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Bonding chemical matrimony

• Ionic bonding
• orderly arrangement of oppositely charged ions
• bonds are moderately strong (salt dissolves in
  water)

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Periodic Table of Elements
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Bonding chemical matrimony

• Covalent bonding
• electrons are shared between atoms
• generally strong
• bonds
• (e.g., diamond, pure C)

Chlorine gas molecule, Cl2
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Bonding chemical matrimony

• Metallic bonding
• electrons drift around from atom to atom
  (e.g., copper, gold, silver)
• good conductors of electrical current
• generally weaker, less common than other bonds

Gold, Au
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The stuff that makes up all matter

• The make-up of solid matter on Earth

Atoms ? Elements ? Compounds ? Minerals ?
Rocks (smallest)
(largest)
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5.2 Composition Structure of Minerals

• KEY IDEA
• A mineral is a naturally occurring element or
  compound that is inorganic and crystalline in
  structure.
• Objectives
• I.D. characteristics of minerals
• Explain how minerals form
• List the physical characteristics of minerals
  that are influenced by their crystalline structure

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Minerals the building blocks of rocks

• Definition of a Mineral
• naturally occurring
• inorganic
• solid
• characteristic crystalline structure
• definite chemical composition

• Definition of a Rock
• A solid aggregate (mixture) of minerals

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Mineral characteristics

• Definition of a Mineral
• naturally occurring
• inorganic
• solid
• characteristic crystalline structure
• definite chemical composition

steel plastic sugar table salt
mercury ice coal
no, 1
no, 1
no, 1,2
YES!
no, 3
YES!
no, 2
basalt obsidian mica gold paper
chalk coral
no, 5
no, 4
YES!
YES!
no, 1,2
no, 2
no, 2
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Mineral characteristics

• Naturally formed
• No substance created artificially is a mineral.
• examples plastic, steel, sugar, paper

• Inorganic
• Anything formed by a living organism and
  containing organic materials is not a mineral.
• examples wood, plants, shells, coal

• Solid
• Liquids and gases are not minerals.
• examples water, petroleum, lava, oxygen

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Element abundances in the crust (pg.96)
All others 1.5
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How Minerals Form

• Many minerals form out of magma, in which atoms,
  molecules, and ions can move freely.
• As magma cools - atoms, molecules ions move
  closer together form chemical bonds that create
  compounds.
• Types of minerals that form depend on the types
  amounts of elements present in the magma.
• Cooling rate of magma determines size of mineral
  grains that form.
• Mineral-forming processes can be gradual
  lengthy.
• Some types of minerals form as water containing
  dissolved ions slowly evaporates.
• Ex halite forms when water evaporates from a
  solution of salt and water
• As H2O molecules evaporate, sodium and chlorine
  ions bond to form the mineral halite.
• New minerals also form when existing minerals are
  transformed by heat, pressure, or chemical
  action.

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Structure of MineralsMineral characteristics

• Characteristic crystalline structure
• must have an ordered arrangement of atoms
• displays repetitive geometric patterns in 3-D
• glass not a mineral (no internal crystalline
  structure)

• Definite chemical composition
• must have consistent chemical formula
• examples gold (Au), quartz (SiO2), orthoclase
  (KAlSi3O8)
• basalt (like many other rocks) contains variable
  ratios of different minerals thus, has no
  consistent formula

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Six Crystal Systems

• See table on page 99

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5.3 Identifying Minerals

• KEY IDEA
• Minerals can be identified by physical and
  chemical properties that include color, luster,
  crystal shape, streak, cleavage, fracture,
  hardness, specific gravity, and reaction to an
  acid.
• Objectives
• I.D. rock-forming minerals by inspection, using
  physical properties such as color, luster
  crystal shape
• I.D. rock-forming minerals using simple tests
  that id both chemical physical properties, like
  streak, specific gravity the acid test

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Crystal Structure Physical Properties5.3
Identifying Minerals

• A. Crystal Form chemistry determines crystal
  shape
• -rarely perfect
• -distinct for each mineral
• B. Color not reliable for diagnosis
• -some distinct olivine, garnet, pyrite
• C. Luster look of surface
• -glassy, pearly, metallic, dull

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• D. Hardness very useful, relative measure
• -compare with scratch-
• Talc baby powder soft
• Gypsum clear (dry wall, sheet rk)
• fingernail 2.5
• Calcite in limestone (cement)
• copper penny 3.5
• Fluorite
• Apatite
• glass 5.5
• 1-4 soft, 6-8 hard, 9-10 very hard
• Feldspar most common
• Quartz in veins of rk in mtns, beach sand
• Topaz gemstone
• 9. Corundum ruby, sapphire

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• E. Streak color of scratch on ceramic plate
• F. Specific Gravity weight
• Ex magnetite- metals
• Has lots of iron- sticks to magnet
• Mineral wt.
• H2O wt.
• Heavy (dark) 3-4
• Light (light) 2.5-3.0
• Very heavy 20 ex lead, gold

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• G. Mineral Cleavage mineral breaks along plane
  
• (flat, smooth, shiny surface) label
  sketches
• 1 plane potato chips slice w/ cleaver
• ex micas
• 2 planes french fries (90 angle)
• ex feldspar
• 3 planes diced cubed, homefries
• ex calcite, salt
• H. Fracture mineral breaks not on a plane
• ex quartz -has no shape when crushed
• I. Others taste (salt), feels slippery
  (graphite), magnetic (magnetite), HCl acid fizzes
  in Calcite (CaCO3)

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How many minerals are there?

• Only 30 occur commonly (whew!)
• Why not more?
• Some combinations are chemically impossible
• Relative abundances of elements dont allow more

• Nearly 4,000 types of minerals

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5.4 Mineral Groups

• KEY IDEA
• The most common minerals in Earths crust are
  silicates and carbonates.
• Objectives
• Describe the properties of the most common
  minerals, silicates carbonates
• Describe tests used to id mineral groups

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5.4 Mineral Groups(Silicates molecular
structure 5.3)

• See table on page 101
• Silicates (Silicon O2) most common type, makes
  up most rx
• ex Fe, Na, Ca, K, Mg like glue, holds
  pyramids together (sketch)
• Individual Tetrahedra SiO4 pyramid, 4 O and 1
  Si atoms
• -tetrah. Combine in diff ways diff minerals
  (sketch)
• 2. Single Chain forms long crystal
• 3. Double Chain long crystal

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• 4. One Plane chains join to form sheet
• ex mica
• Biatite- black mica
• muscovite- white mica
• Clays- microse crystals
• slippery- sheets, slip past eachother
• minerals microscopic
• 5. 3-D Network sheets held together, strong
  hard
• Feldspars- most common minerals, 50 of rx made
  of
• 1. orthoclase- lots of potassium (K), found in
  granite, tan or pink
• 2. plagioclase- white specks in volc rx
• Quartz- 2nd most abundant mineral
• -all tetra. w/ no ions (glue) hard
• ex amethyst (Mg in quartz), citrine, smoky
  quartz (Fe)
• -color from impurities

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• B. Non-Silicates- less common, more import.
  economically, mines
• 1. Carbonates- has CO3
• Ex calcite (cement) ex CaCO3 (limestone,
  shells, coral)
• 2. Oxides- metal oxygen
• Most ores (minerals that we mine to get metals)
• Ex hematite (iron, hemoglobin in blood caries
  O2)
• 3. Sulfides- metal sulfur
• Ex galena, lead, copper
• 4. Sulfates- has SO4 ex gypsum (dry
  wall)
• 5. Hydroxides-has OH ex bauxite (aluminum)
• 6. Halides- this is the mineral name for salt!
  (usually with with chlorine) ex halite (salt)
• 7. Native elements- pure elements ex diamond,
  gold

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• Gemstones (not a mineral group)
• Rare, hard, (doesnt scratch, but not all)
• Known for beauty
• Ex diamond, topaz, sapphire, ruby, amethyst,
  emerald