Atomic Bonding

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Atomic Bonding Water

• But first DO NOW
• Please copy the following chart into your notes
  (leave plenty of space)

Property of Water Description Cause
Water is a strong solvent
Ice is less dense than liquid water
Cohesion , Adhesion, and high surface tension
Water resists increases in temperature
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Compounds

• An atomic bond is a force which joins atoms
  together to form a molecule

H
O
Atomic bond
Water
H
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How Atomic Bonds Work

• Electrons are responsible for atomic bonding.
• There are 3 ways electrons can interact to form
  bonds

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Ionic Bonds STRONG

• An atom loses 1 or more electrons, giving it a
  positive charge.
• Another atom gains the electron(s) and becomes
  negatively charged
• - ions attract.

-

e-
e-
Cl
e-
Na
e-
e-
e-
e-
e-
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Covalent bonds STRONG

• 2 atoms share a pair of electrons

H
H
e-
e-
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Polar Bonds STRONG

• In a polar bond, electrons are shared unevenly.
• Since electrons are negative, the atom that
  attracts electrons the most becomes a little
  negative, and the atom losing the electrons
  becomes a little positive.

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Water is Special

• Property 1 Water resists changes in
  temperature
• Demonstration
• High Specific Heat Capacity
• Related Property high melting boiling points

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Related High Melting Boiling Points
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High Surface Tension
Waters high surface tension causes
Adhesion Water sticking to other surfaces
Cohesion Water sticking to Water
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Solvent Properties

• Water is very good at dissolving substances.
• Universal Solvent

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Density Anomaly

• Ice floats on water!
• Water is one of the only compounds known that
  gets less dense when it freezes!

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What Were Those Properties?
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Water is a polar molecule. The O-H bonds are
polar covalent
Molecules with positive and negative parts are
called polar molecules. Polar molecules form
hydrogen bonds
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New Bond - Hydrogen Bond Pathetically WEAK!

• A Hydrogen bond is a weak bond between 2
  different polar molecules

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WHY WATER HAS SPECIAL PROPERTIES
Water has all of those weird properties happen
because of 1 simple thing
HYDROGEN BONDS
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Water is a polar molecule

• It has a positive and negative side, causing
  hydrogen bonds

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HOMEWORK

• Read Section 3-1, pp. 49-51
• Quiz tomorrow elements, compounds, atoms
  molecules parts of atoms, types of atomic bonds.
  NO WATER STUFF
• COACH CLASS TODAY AFTER SCHOOL