Atoms in Combination: The Chemical Bond

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Atoms in Combination The Chemical Bond

• Chapter 10

Great Idea Atoms bind together in chemical
reactions by the rearrangement of electrons
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Electron Shells, Periodic Table, and Chemical
Bonds

• Electron Shells and Periodic Table
• metal, non metal, metalloid
• valence electrons
• Chemical Bond rearrange electrons to fill a
  shell to form a stable configuration
• Give electrons
• Accept electrons
• Share electrons

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Types of Chemical Bonds
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Ionic Bonds
Example Na and Cl

• Atoms donate or accept electron (s) to become
  ions
• Ions bond together by electrostatic attraction

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Ionic Bonds (continued)
Ionic Bonding of Three Atoms MgCl2
Mg not Ca
Electron Configurations of Magnesium and Chloride
before (left) and after (right) electrons been
transferred.
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Metallic Bonds

• Metal atoms give away electrons and share
  electrons.
• Electron cloud doesnt belong to any one metal
  ion.
• Characteristics
• Shiny, conduct electricity, malleable (can change
  shape permanently by stress)

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Covalent Bonds

• Share electrons with neighboring atoms

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Covalent Bonds Bond of Life

• Carbon backbone of lifes essential molecules
• Single bond, double bond
• Chain, branch, ring, 3D almost any shape
• Organic Chemistry study of Carbon-based
  molecules

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Covalent Bonds (continued)

• Silicon
• The most important semiconductor material that
  has been changing the quality of our lives.

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Polarization and Hydrogen Bonds

• Example Water H2O

• Polar molecules
• Hydrogen Bond
• Weak bond
• In many molecules they occur repeatedly so play a
  major role

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Van der Waals Forces

• Weak bonds between electrically neutral
  molecules.
• Examples
• Graphite
• Clay

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States of Matter

• Three states of water gas, liquid, solid

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States of Matter Gases, Plasma, Liquids, and
Solids

• Gas
• No fixed volume or shape
• Expands to fill container
• Plasma
• At extreme temperatures, electrons are ripped off
  from atoms. Positive nuclei moves in a sea of
  electrons. This collection of charged objects is
  called Plasma.
• It is the least familiar to us, but 99.9 of all
  visible matter in universe is plasma.
• Liquids
• Fixed volume, not fixed shape
• Surface tension
• Solids
• fixed volume and shape

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Solids

• Crystals
• Regular repeating sequence over thousands of
  atoms
• Glasses
• Regular on a local scale but irregular over a
  distance of 3-4 atoms
• Polymers
• Chains of molecules
• Plastics

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Homework

• Reading PP 192-203
• More Exercises Problems
• 1-6, 8, 12, 17-22, 24-26, 29,31,37-39