Chemical

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Chemical
How do elements interact with each other?
Bonding Interactions
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Whats the Difference?

• Make Careful Observations (write down)
• 2 white powders
• Dissolved in water
• When heated
• Chemical formulas of each

NaCl
C12H22O12
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How are they different?

• In a small group, come up with as many
  differences/similarities
• Think about
• The electron configs of their elements (chapter
  6)
• Their place on the periodic table (chapter 7)
• Their sizes (chapter 7)
• The ionization energies/electron affinities
  (chapter 7)
• Jot down similarities/differences on a white
  board

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3 Ways Atoms Interact

• How to tell them apart
• Ionic
• Metals combined with non-metals
• Covalent
• 2 or more non-metals
• Metallic
• The way metallic elements interact with themselves

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Ionic Interactions

• How they form
• How to write them
• What their properties are

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Chapter 8 Questions

• Why does tap water conduct electricity?
• Forget that question, why do PICKLES conduct
  electricity!?

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Valence Electron Review

• Valence Electrons
• Electrons in the outer shell of an atom
• Range from 1 8
• Be able to find how many valence electrons an
  element has

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Lewis Dot Structure

• Lewis dot structures represent the amount of
  Valence electrons
• Atoms are superficial when it comes to bonding
  (only care about the outer shells), this is very
  important

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Lewis Structure Practice

• Write the Lewis Dot Structure of the following
  atoms
• Mg
• Al
• O
• Ar

2 valence e-
3 valence e-
6 valence e-
8 valence e-
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The Octet Rule

• Atoms tend to gain, lose, or share electrons in
  order to acquire a full set of valence electrons
• For most atoms, this full set is 8 (hence the
  Octet Rule)
• Another way to think of it Noble Gas Rule
• Atoms want to be like the noble gases

1s22s22p63s23p5
1s22s22p63s1
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What Ions do they form?

• We can predict what ions elements form by using
  the octet rule

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How elements differ

• Observe the difference between
• Argon (Ar) Potassium (K)
• Look at their electron configurations

Argon 1s22s22p63s23p6 Potassium
1s22s22p63s23p64s1
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Ion Review

• Remember Ions
• Positive ions are cations
• They have more protons () than electrons (-)
• Negative ions are anions
• They have more electrons (-) than protons ()
• Positives and Negatives attract each other
• Joke time!

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Hmmm..

• Guess what happens..

Now what?
Na
Cl
Na lost 1 electron so it is
Cl gained 1 electron so it is
-

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Attraction
Na
Cl -

• Ions have now formed, and are attracted to each
  other
• An Ionic Interaction is formed NaCl

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Check-Up

• Chapter 8 Assessment
• 2) Why do ions form?
• They gain more stable electron configs by losing
  or gaining electrons
• 3) What family of elements is relatively
  unreactive and why?
• Noble gases because they have 8 electrons in
  their outermost level
• 4) How do positive ions form? How do negative
  ions form?
• Positive when atoms lose electrons
• Negative when atoms gain electrons
• 5) Predict the charge of the ions of the
  following atoms
• Nitrogen
• Sulfur
• Barium
• Lithium

-3
-2
2
1
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Lewis Structure of NaCl
Lets look at this reaction!
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Chapter 8 Questions

• Why does tap water conduct electricity?
• Forget that question, why do PICKLES conduct
  electricity!?

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Ionic Interaction Properties

• Electrons are transferred creating Ions
• Positively charged ions are attracted to
  negatively charged ions
• Properties
• High melting points
• Very brittle
• Many dissolve in H2O
• Conductors of electricity when dissolved
• or melted (electrolyte)
• Arrange in crystal lattice

• Links
• Ionic Structure
• Dissolving an Ionic Compound

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Revisiting the Questions

• Why does tap water conduct electricity?
• Why do PICKLES conduct electricity!?

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How Ions Combine
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Section 8.3 Question

• What happens to the mass of steel wool when it is
  burned?
• Make a prediction!

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Forming Ionic Compounds

• Why did we use puzzle pieces?
• Needs to be a Positive with a Negative
• Positives and Negatives attract, but need to
  attract in equal magnitude

Na 1
Cl 1-
Sodium Ions (Na 1) and Chlorine Ions (Cl 1-)
combine in a 11 ratio to form NaCl
11 is the Formula Unit
Formula Unit The simplest ratio of the ions in a
compound
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Cl 1-
0

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Forming Ionic Compounds

• Needs to be a Positive with a Negative
• Positives and Negatives attract, but need to
  attract in equal magnitude

Na
Cl -
Mg 2
Cl -
Mg 2
Na
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Few Rules

• Write the Cation first
• ()(-)
• Balance the Charges
• Positives must equal negatives

-
-


-
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Examples

• Combining

How can we balance these charges?
LCM
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Periodic Table Ions

• The same Periodic table that showed us electron
  configs, now shows us IONS
• Remember elements want to be like noble gases
  so many of them have common ions

Lose 1
Noble Gases
1
4
2
Lose 2
Gain 1
Gain 2
Gain 3
Lose 4
-3
-2
-1
Vary in Charge
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What about the Red Block
Vary in Charge

• These elements have variable charge
• Example Fe could be 3, 2 or 6

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Subscripts vs Charge

• Charge
• Only written on an ion, not on a neutral compound
• Written above as opposed to below

Cl
-
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Subscripts vs Charge

• Subscripts Shows the ratios of atoms
• The number proceeds the element
• 1s are not written
• Implies that the atoms are BONDED
• Examples

Ca
2 atoms of Calcium
2
Cl
Mg
1 atom of Magnesium 2 atoms of Chlorine
2
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Subscripts

• 2 Cl- is different from Cl2

Represents 2 atoms of chlorine ions
Represents 2 atoms of chlorine bonded together
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Try Some

• How many atoms what is the charge?

2 Mg2 2 atoms Mg 4 Charge
2 Zn2
3 Al3
3 O2
4 Ca2
3 Li
Cl2
H2O
KBr
C6H12O6
Al2O3
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Covalent Bonds Test Topics

• Lewis Structures
• Formal Charge
• Resonance Structures
• Molecular Geometry
• Naming of Covalent Compounds

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Types of Covalent Bonds

• Non-polar covalent
• Equal sharing of bonding electrons
• Polar covalent
• Unequal sharing of bonding electrons
• How do we know which one?
• Black White tug of war practice

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Electronegativity

• Electronegativity is how badly an atom wants an
  electron
• Loose ball drill who wants it more?

F
B
4.0
2.0
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Electronegativity
What do differences in electronegativities lead
to?
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Electron density distribution
F-F
The greater the difference in electronegativity,
the more polar the bond
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Sample problem 8.4

• In each case, which bond is more polar
• A) BCl or CCl
• B) PF or PCl
• Indicate in each case which atom has the partial
  negative charge

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Geometries of Atoms

• 2 types of geometries
• Electron Domain geometry
• Molecular geometry

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Geometries

• Balloons electron domains
• Electron domain
• Bonding pair of electrons
• Nonbonding pair of electrons

4 Electron Domains
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Electron-Domain Geometries

• They describe the arrangement of electron domains
  around a central atom
• They do not differentiate between bonds lone
  pairs

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Electron-Domain Geometries

• They describe the arrangement of electron domains
  around a central atom
• They do not differentiate between bonds lone
  pairs

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Molecular Geometry

• Only describes the geometry of the atoms in a
  molecule

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Molecular Geometry

• Only describes the geometry of the atoms in a
  molecule

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Molecular Geometry

• Only describes the geometry of the atoms in a
  molecule

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Molecular Geometry

• Only describes the geometry of the atoms in a
  molecule