3Minute WarmUp: Chemical Bonds first section

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3-Minute Warm-Up Chemical Bonds (first section)

• Decide if these statements are true. If they are
  not true, correct them.
• 1. An atom can form more than one covalent bond
  with another atom.
• 2. Covalent bonds always have equal sharing of
  electrons.
• 3. A molecules structure can influence how it
  reacts with other molecules.

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Unit 2 Chemical InteractionsChapter 2 Chemical
Bonds and Compounds

• Section 3 Substances properties depend on their
  bonds

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Then and Now

• BEFORE, you learned
• Chemical bonds hold the atoms of compounds
  together
• Chemical bonds involve the transfer or sharing of
  electrons
• Molecules have a structure

• NOW, you will learn
• How metal atoms form chemical bonds with one
  another
• How ionic and covalent bonds influence
  substances properties

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Set Learning Goals

• Students will
• Describe how metal atoms form chemical bonds with
  one another.
• Analyze how ionic and covalent bonds influence
  substances properties.
• Identify different forms of the same element.

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Section 2.2.3 Vocabulary

• Metallic Bond

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Properties of metals

• Properties come from metallic bonds
• All electrons shared equally
• 1 Good conductors of
• Heat
• Electricity
• Why?
• Because the electrons move freely
• 2 High melting points
• All are solid at room temp (except for Mercury)
• 3 Easily shaped
• Can be made into wire and coins (and other things)

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• What property of the electrons in a metal gives
  the metal its properties?
• They move easily.

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Properties of Ionic Compounds

• Usually solid at room temperature
• High melting and boiling points
• Lots of energy required to break the bonds
• Hard
• Brittle
• Poor conductors of electricity in solid form
• Electrons dont move!
• Many dissolve easily
• Become positive and negative ions in solution
• - These DO conduct electricity because the
  electrons still move

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Examples

• Sports Drinks
• Our bodies need ionic solutions to carry
  electrical messages sports drinks replenish
  those (replenish meaning replace)
• Mineral Hot Springs
• Yellowstone

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Properties of Covalent Molecules

• Almost opposite that of ionic compounds
• Melting/boiling points usually lower than ionic
  compounds
• Do not usually dissolve in water
• makes them poor conductors of electricity because
  the electrons do not move

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Bond (not the) Same Bond

• Covalent bonds are weird particularly Carbon
• Diamonds
• Hardest substance known
• Beautiful gems
• Great on jewelry
• Made of Carbon
• Graphite
• Soft lead of pencils
• Marks easily
• Made of Carbon
• Fullerene
• Used in space research
• Looks like a soccer ball
• Also carbon

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See how they differ?
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Questions 2.2.3

• KEY CONCEPTS
• 1. How do metal atoms bond together?
• 2. Why do ionic compounds have high melting
  points?
• 3. What are three forms of the element carbon?
• CRITICAL THINKING
• 4. Apply A compound known as cubic boron nitride
  has a structure similar to that of a diamond.
  What properties would you expect it to have?
• 5. Infer Sterling silver is a combination of
  silver and copper. How are the silver and copper
  atoms held together?
• CHALLENGE
• 6. Infer Why might the water in mineral springs
  be a better conductor of electricity than
  drinking water?