Sodium in Water Calcium in Water

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Sodium in WaterCalcium in Water
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We will use
iltclicker GO or iltclicker or iltclicker2
First Trial on Friday
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PRACTICE CLICKER QUESTION 1

• The two primary factors that affect the structure
  of a material are
• Performance and properties
• Composition and performance
• Composition and processing
• Processing and performance

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Interrelationships
Processing
Composition
Structure
Properties
Performance
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Primary Classes of MaterialsExamples of changes
in composition

• Metalsincrease C content of Fe
• CeramicsSubstitute K with Ca
• PolymersSubstitute H with F

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Interrelationships
Processing
Composition
Structure
Properties
Performance
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Processing Clay becomes Fired clay pottery
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SEM Clay vs. Fired Clay
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Processing affects structure
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Discrete clay quartz particles melt fuse into
vitreous material.
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Processing Copper
Copper Tubing
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Processing
Metal Ore Mine
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Processing Copper
Copper Ore
Smelting Process
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Processing Copper
99.9 Pure copper
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Interrelationships
Processing
Composition
Structure
Properties
Performance
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Structuresall scalesExample BCC crystal
Molybdenum
Atomic
Subatomic
Microscopic
Macroscopic
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Interrelationships
Processing
Composition
Structure
Properties
Performance
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Properties
Brittleness
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Properties

• Response to imposed stimulus.
• If I drop it (stimulus), will it break
  (response)?
• mechanical
• electrical
• thermal
• deteriorative
• magnetic
• optical

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Mechanical PropertyElasticityrecoverable
deformation

• Paper clip
• under normal use

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Mechanical PropertyPlasticitypermanent
deformation

• Paper clip
• under abuse

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Plasticity by design

• Radial profile
• segments

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Plasticity by accident

• Street lamp
• damaged during
• storm
• (Bridgeport, CN)

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Mechanical PropertyBrittleness

• Pressure vessel fails during hydraulic test

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Deteriorative PropertyCorrosiveness

• Corroded ship at Guantanamo

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Properties of copper ore vs refined copper

• Response to imposed stimulus.
• Mechanical
• Electrical
• Thermal
• Deteriorative

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The Humble Hanger
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The Humble Hanger
Coat hanger in 1880s schoolhouse
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Humble Hanger What determines performance?
Processing
Composition
Structure
Properties
Performance
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PRACTICE CLICKER QUESTION 2

• Which of the following are considered material
  properties?
• Metals, ceramics, polymers
• Strength, conductivity, brittleness
• Increasing the Si/O2 ratio
• Cubic, orthorhombic, tetragonal

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PRACTICE CLICKER QUESTION 3

• Which of the following are examples of changes in
  composition?
• Increasing strength
• Increasing size of a crystal
• Increasing the Si/O2 ratio
• Changing the crystal structure
• Applying more heat

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PRACTICE CLICKER QUESTION 3

• Which of the following are examples of changes in
  processing?
• Increasing strength
• Increasing size of a crystal
• Increasing the Si/O2 ratio
• Changing the crystal structure
• Applying more heat

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Chapter 2

• Periodic Table2.1, 2.2, 2.4

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Practice Clicker Question 3Reading Assignment

• The number of electrons in an electrically
  neutral atom is described by
• The atomic mass
• The atomic number
• The mole
• The isotope ratio

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Periodic Table of the Elements
From W. D. Callister (2007) Materials Science and
Engineering An Introduction, 7/e. New York
Wiley Sons
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Practice Clicker Question 4Reading Assignment

• If you were asked to identify elements from the
  periodic table that have similar chemical and
  physical properties, which would you choose?
• Elements that lie in the same row
• Elements that lie in the same column
• Elements that lie along a diagonal
• None of the above Properties vary
• dramatically between neighboring elements

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Alkali Metals
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Alkali Metals

• Fun to throw in a lake
• Sodium in Water

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Alkali Earth Metals
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Alkali Earth Metals

• Relatively soft metals.
• Reactive, but not explosive
• Calcium in Water

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Non-metals
Transition Metals
Intermediate
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Transition Metals

• Workhorse of the periodic table structural
  integrity, conductors

Intermediates
Semi-conductors, metallic luster, too brittle for
structural integrity
Nonmetals
Insulators, brittle, readily gain/share electrons
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Chapter 2

• Bonding2.62.8

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Bohr Atomic Model
Sodium
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Rules of bonding

• 1. Ordinarily, matter is electrically neutral.
• 2. Some electron numbers are especially stable
• 3. Dipoles almost always occur.
• (Important to secondary bonding)

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Rule 1 Electrical Neutrality
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Rule 2 Stable Configurations

• Some electron configurations
• are especially stable.
• (Think noble gases)

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Noble Gasses
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The Periodic Table
Columns Similar Valence Structure
Adapted from Fig. 2.6, Callister Rethwisch 8e.
Electronegative elements Readily acquire
electrons to become - ions.
Electropositive elements Readily give up
electrons to become ions.
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Electronegativites
Tend to increase left to right and bottom to top
Fig. 2.7
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Rule 3 Dipoles

• Covered later in lecture

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Section 2.6

• Primary Interatomic Bonds

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Types of Bonding

• All but Noble gases are unstable
• Type of bonding depends on how to gain
  stability

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Types of Bonding

• Ionic
• Covalent
• Metallic
• Van der Waals (Secondary)

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Practice Clicker Question 5Reading Assignment

• Ionic bonding involves
• Sharing of electrons
• Electrostatic forces
• Dipole bonds
• Valence electrons moving among atoms to form a
  sea of electrons

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Rule 2 Stable Configurations

• Some electron configurations
• are especially stable.
• (Think noble gases)

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Example Na, Cl
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Rule 1 Electrical Neutrality

• Opposites attract

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1) Ionic Bonding

• Atoms take/give electrons to neighbor
• Often 1 metallic 1 non-metallic
• (Elements from opposite sides of table)

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2) Covalent bonding
Atoms Share Electrons
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Example H2O
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2) Covalent bonding

• Adjacent atoms share electrons to achieve
  stable e- configuration

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Reality check
ionic
covalent
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3) Metallic Bonding

• Share electrons
• Orbitals never completely filled
• Electrons jump from atom to atom

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Section 2.7

• Secondary or Van der Waals Bonding

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Rule 3 Dipoles almost always occur
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4) Secondary (Van der Waals) bonding

• Weak compared to primary bonds
• Can significantly affect material properties

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4) Secondary (Van der Waals) bonding
Fluctuating induced dipole moments
Ion core
Before
Ion core

Ion core
Ion core

After



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4) Secondary (Van der Waals) bonding

• Permanent Dipole Bonds
• Permanent dipole moments in the molecule.
• Bonds stronger than for Fluctuating
• Example H2O

H
H
H
O


O


O


H
H
H
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• Permanent dipole moments

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Electronegativites
Fig. 2.7
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Practice Clicker Question 6

• Materials which are ionically bonded tend to have
  these two mechanical properties
• Hard and brittle
• Hard and ductile
• Soft and brittle
• Soft and ductile
• None of these